diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown --- a/CHANGELOG.markdown +++ b/CHANGELOG.markdown @@ -1,179 +1,184 @@ -5.5.13 [2022.09.12] -------------------- -* Make the `Biapplicative` instances for tuples lazy, to match their `Bifunctor` - instances. - -5.5.12 [2022.05.07] -------------------- -* Backport an upstream GHC change which removes the default implementation of - `bitraverse`. Per the discussion in - https://github.com/haskell/core-libraries-committee/issues/47, this default - implementation was completely broken, as attempting to use it would always - result in an infinite loop. - -5.5.11 [2021.04.30] -------------------- -* Allow building with `template-haskell-2.18` (GHC 9.2). - -5.5.10 [2021.01.21] -------------------- -* Fix a bug in which `deriveBifoldable` could generate code that triggers - `-Wunused-matches` warnings. - -5.5.9 [2020.12.30] ------------------- -* Explicitly mark modules as Safe or Trustworthy. - -5.5.8 [2020.10.01] ------------------- -* Fix a bug in which `deriveBifunctor` would fail on sufficiently complex uses - of rank-n types in constructor fields. -* Fix a bug in which `deriveBiunctor` and related functions would needlessly - reject data types whose two last type parameters appear as oversaturated - arguments to a type family. - -5.5.7 [2020.01.29] ------------------- -* Add `Data.Bifunctor.Biap`. - -5.5.6 [2019.11.26] ------------------- -* Add `Category`, `Arrow`, `ArrowChoice`, `ArrowLoop`, `ArrowZero`, and - `ArrowPlus` instances for `Data.Bifunctor.Product`. - -5.5.5 [2019.08.27] ------------------- -* Add `Eq{1,2}`, `Ord{1,2}`, `Read{1,2}`, and `Show{1,2}` instances for data - types in the `Data.Bifunctor.*` module namespace where possible. The - operative phrase is "where possible" since many of these instances require - the use of `Eq2`/`Ord2`/`Read2`/`Show2`, which are not avaiable when - built against `transformers-0.4.*`. - -5.5.4 [2019.04.26] ------------------- -* Support `th-abstraction-0.3` or later. -* Don't incur a `semigroup` dependency on recent GHCs. - -5.5.3 [2018.07.04] ------------------- -* Make `biliftA2` a class method of `Biapplicative`. -* Add the `traverseBia`, `sequenceBia`, and `traverseBiaWith` functions for - traversing a `Traversable` container in a `Biapplicative`. -* Avoid incurring some dependencies when using recent GHCs. - -5.5.2 [2018.02.06] ------------------- -* Don't enable `Safe` on GHC 7.2. - -5.5.1 [2018.02.04] ------------------- -* Test suite fixes for GHC 8.4. - -5.5 [2017.12.07] ----------------- -* `Data.Bifunctor.TH` now derives `bimap`/`bitraverse` - implementations for empty data types that are strict in the argument. -* `Data.Bifunctor.TH` no longer derives `bifoldr`/`bifoldMap` implementations - that error on empty data types. Instead, they simply return the folded state - (for `bifoldr`) or `mempty` (for `bifoldMap`). -* When using `Data.Bifunctor.TH` to derive `Bifunctor` or `Bitraversable` - instances for data types where the last two type variables are at phantom - roles, generated `bimap`/`bitraverse` implementations now use `coerce` for - efficiency. -* Add `Options` to `Data.Bifunctor.TH`, along with variants of existing - functions that take `Options` as an argument. For now, the only configurable - option is whether derived instances for empty data types should use the - `EmptyCase` extension (this is disabled by default). - -5.4.2 ------ -* Make `deriveBitraversable` use `liftA2` in derived implementations of `bitraverse` when possible, now that `liftA2` is a class method of `Applicative` (as of GHC 8.2) -* Backport slightly more efficient implementations of `bimapDefault` and `bifoldMapDefault` - -5.4.1 ------ -* Add explicit `Safe`, `Trustworthy`, and `Unsafe` annotations. In particular, annotate the `Data.Bifoldable` module as `Trustworthy` (previously, it was inferred to be `Unsafe`). - -5.4 ---- -* Only export `Data.Bifoldable` and `Data.Bitraversable` when building on GHC < 8.1, otherwise they come from `base` -* Allow TH derivation of `Bifunctor` and `Bifoldable` instances for datatypes containing unboxed tuple types - -5.3 ---- -* Added `bifoldr1`, `bifoldl1`, `bimsum`, `biasum`, `binull`, `bilength`, `bielem`, `bimaximum`, `biminimum`, `bisum`, `biproduct`, `biand`, `bior`, `bimaximumBy`, `biminimumBy`, `binotElem`, and `bifind` to `Data.Bifoldable` -* Added `Bifunctor`, `Bifoldable`, and `Bitraversable` instances for `GHC.Generics.K1` -* TH code no longer generates superfluous `mempty` or `pure` subexpressions in derived `Bifoldable` or `Bitraversable` instances, respectively - -5.2.1 ----- -* Added `Bifoldable` and `Bitraversable` instances for `Constant` from `transformers` -* `Data.Bifunctor.TH` now compiles warning-free on GHC 8.0 - -5.2 ------ -* Added several `Arrow`-like instances for `Tannen` so we can use it as the Cayley construction if needed. -* Added `Data.Bifunctor.Sum` -* Added `BifunctorFunctor`, `BifunctorMonad` and `BifunctorComonad`. -* Backported `Bifunctor Constant` instance from `transformers` - -5.1 ---- -* Added `Data.Bifunctor.Fix` -* Added `Data.Bifunctor.TH`, which permits `TemplateHaskell`-based deriving of `Bifunctor`, `Bifoldable` and `Bitraversable` instances. -* Simplified `Bitraversable`. - -5 -- -* Inverted the dependency on `semigroupoids`. We can support a much wider array of `base` versions than it can. -* Added flags - -4.2.1 ------ -* Support `Arg` from `semigroups` 0.16.2 -* Fixed a typo. - -4.2 ---- -* Bumped dependency on `tagged`, which is required to build cleanly on GHC 7.9+ -* Only export `Data.Bifunctor` when building on GHC < 7.9, otherwise it comes from `base`. - -4.1.1.1 -------- -* Added documentation for 'Bifoldable' and 'Bitraversable' - -4.1.1 ------ -* Added `Data.Bifunctor.Join` -* Fixed improper lower bounds on `base` - -4.1.0.1 -------- -* Updated to BSD 2-clause license - -4.1 ---- -* Added product bifunctors - -4.0 ---- -* Compatibility with `semigroupoids` 4.0 - -3.2 ---- -* Added missing product instances for `Biapplicative` and `Biapply`. - -3.1 ------ -* Added `Data.Biapplicative`. -* Added the `Clown` and `Joker` bifunctors from Conor McBride's "Clowns to the left of me, Jokers to the right." -* Added instances for `Const`, higher tuples -* Added `Tagged` instances. - -3.0.4 ------ -* Added `Data.Bifunctor.Flip` and `Data.Bifunctor.Wrapped`. - -3.0.3 ---- -* Removed upper bounds from my other package dependencies +5.5.14 [2022.12.07] +------------------- +* Define `Functor`, `Foldable`, and `Traversable` instances for `Sum` and + `Product`. + +5.5.13 [2022.09.12] +------------------- +* Make the `Biapplicative` instances for tuples lazy, to match their `Bifunctor` + instances. + +5.5.12 [2022.05.07] +------------------- +* Backport an upstream GHC change which removes the default implementation of + `bitraverse`. Per the discussion in + https://github.com/haskell/core-libraries-committee/issues/47, this default + implementation was completely broken, as attempting to use it would always + result in an infinite loop. + +5.5.11 [2021.04.30] +------------------- +* Allow building with `template-haskell-2.18` (GHC 9.2). + +5.5.10 [2021.01.21] +------------------- +* Fix a bug in which `deriveBifoldable` could generate code that triggers + `-Wunused-matches` warnings. + +5.5.9 [2020.12.30] +------------------ +* Explicitly mark modules as Safe or Trustworthy. + +5.5.8 [2020.10.01] +------------------ +* Fix a bug in which `deriveBifunctor` would fail on sufficiently complex uses + of rank-n types in constructor fields. +* Fix a bug in which `deriveBiunctor` and related functions would needlessly + reject data types whose two last type parameters appear as oversaturated + arguments to a type family. + +5.5.7 [2020.01.29] +------------------ +* Add `Data.Bifunctor.Biap`. + +5.5.6 [2019.11.26] +------------------ +* Add `Category`, `Arrow`, `ArrowChoice`, `ArrowLoop`, `ArrowZero`, and + `ArrowPlus` instances for `Data.Bifunctor.Product`. + +5.5.5 [2019.08.27] +------------------ +* Add `Eq{1,2}`, `Ord{1,2}`, `Read{1,2}`, and `Show{1,2}` instances for data + types in the `Data.Bifunctor.*` module namespace where possible. The + operative phrase is "where possible" since many of these instances require + the use of `Eq2`/`Ord2`/`Read2`/`Show2`, which are not avaiable when + built against `transformers-0.4.*`. + +5.5.4 [2019.04.26] +------------------ +* Support `th-abstraction-0.3` or later. +* Don't incur a `semigroup` dependency on recent GHCs. + +5.5.3 [2018.07.04] +------------------ +* Make `biliftA2` a class method of `Biapplicative`. +* Add the `traverseBia`, `sequenceBia`, and `traverseBiaWith` functions for + traversing a `Traversable` container in a `Biapplicative`. +* Avoid incurring some dependencies when using recent GHCs. + +5.5.2 [2018.02.06] +------------------ +* Don't enable `Safe` on GHC 7.2. + +5.5.1 [2018.02.04] +------------------ +* Test suite fixes for GHC 8.4. + +5.5 [2017.12.07] +---------------- +* `Data.Bifunctor.TH` now derives `bimap`/`bitraverse` + implementations for empty data types that are strict in the argument. +* `Data.Bifunctor.TH` no longer derives `bifoldr`/`bifoldMap` implementations + that error on empty data types. Instead, they simply return the folded state + (for `bifoldr`) or `mempty` (for `bifoldMap`). +* When using `Data.Bifunctor.TH` to derive `Bifunctor` or `Bitraversable` + instances for data types where the last two type variables are at phantom + roles, generated `bimap`/`bitraverse` implementations now use `coerce` for + efficiency. +* Add `Options` to `Data.Bifunctor.TH`, along with variants of existing + functions that take `Options` as an argument. For now, the only configurable + option is whether derived instances for empty data types should use the + `EmptyCase` extension (this is disabled by default). + +5.4.2 +----- +* Make `deriveBitraversable` use `liftA2` in derived implementations of `bitraverse` when possible, now that `liftA2` is a class method of `Applicative` (as of GHC 8.2) +* Backport slightly more efficient implementations of `bimapDefault` and `bifoldMapDefault` + +5.4.1 +----- +* Add explicit `Safe`, `Trustworthy`, and `Unsafe` annotations. In particular, annotate the `Data.Bifoldable` module as `Trustworthy` (previously, it was inferred to be `Unsafe`). + +5.4 +--- +* Only export `Data.Bifoldable` and `Data.Bitraversable` when building on GHC < 8.1, otherwise they come from `base` +* Allow TH derivation of `Bifunctor` and `Bifoldable` instances for datatypes containing unboxed tuple types + +5.3 +--- +* Added `bifoldr1`, `bifoldl1`, `bimsum`, `biasum`, `binull`, `bilength`, `bielem`, `bimaximum`, `biminimum`, `bisum`, `biproduct`, `biand`, `bior`, `bimaximumBy`, `biminimumBy`, `binotElem`, and `bifind` to `Data.Bifoldable` +* Added `Bifunctor`, `Bifoldable`, and `Bitraversable` instances for `GHC.Generics.K1` +* TH code no longer generates superfluous `mempty` or `pure` subexpressions in derived `Bifoldable` or `Bitraversable` instances, respectively + +5.2.1 +---- +* Added `Bifoldable` and `Bitraversable` instances for `Constant` from `transformers` +* `Data.Bifunctor.TH` now compiles warning-free on GHC 8.0 + +5.2 +----- +* Added several `Arrow`-like instances for `Tannen` so we can use it as the Cayley construction if needed. +* Added `Data.Bifunctor.Sum` +* Added `BifunctorFunctor`, `BifunctorMonad` and `BifunctorComonad`. +* Backported `Bifunctor Constant` instance from `transformers` + +5.1 +--- +* Added `Data.Bifunctor.Fix` +* Added `Data.Bifunctor.TH`, which permits `TemplateHaskell`-based deriving of `Bifunctor`, `Bifoldable` and `Bitraversable` instances. +* Simplified `Bitraversable`. + +5 +- +* Inverted the dependency on `semigroupoids`. We can support a much wider array of `base` versions than it can. +* Added flags + +4.2.1 +----- +* Support `Arg` from `semigroups` 0.16.2 +* Fixed a typo. + +4.2 +--- +* Bumped dependency on `tagged`, which is required to build cleanly on GHC 7.9+ +* Only export `Data.Bifunctor` when building on GHC < 7.9, otherwise it comes from `base`. + +4.1.1.1 +------- +* Added documentation for 'Bifoldable' and 'Bitraversable' + +4.1.1 +----- +* Added `Data.Bifunctor.Join` +* Fixed improper lower bounds on `base` + +4.1.0.1 +------- +* Updated to BSD 2-clause license + +4.1 +--- +* Added product bifunctors + +4.0 +--- +* Compatibility with `semigroupoids` 4.0 + +3.2 +--- +* Added missing product instances for `Biapplicative` and `Biapply`. + +3.1 +----- +* Added `Data.Biapplicative`. +* Added the `Clown` and `Joker` bifunctors from Conor McBride's "Clowns to the left of me, Jokers to the right." +* Added instances for `Const`, higher tuples +* Added `Tagged` instances. + +3.0.4 +----- +* Added `Data.Bifunctor.Flip` and `Data.Bifunctor.Wrapped`. + +3.0.3 +--- +* Removed upper bounds from my other package dependencies diff --git a/LICENSE b/LICENSE --- a/LICENSE +++ b/LICENSE @@ -1,26 +1,26 @@ -Copyright 2008-2016 Edward Kmett - -All rights reserved. - -Redistribution and use in source and binary forms, with or without -modification, are permitted provided that the following conditions -are met: - -1. Redistributions of source code must retain the above copyright - notice, this list of conditions and the following disclaimer. - -2. Redistributions in binary form must reproduce the above copyright - notice, this list of conditions and the following disclaimer in the - documentation and/or other materials provided with the distribution. - -THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR -IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED -WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE -DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR -ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL -DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS -OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) -HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, -STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN -ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -POSSIBILITY OF SUCH DAMAGE. +Copyright 2008-2016 Edward Kmett + +All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions +are met: + +1. Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + +2. Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + +THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR +IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR +ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +POSSIBILITY OF SUCH DAMAGE. diff --git a/README.markdown b/README.markdown --- a/README.markdown +++ b/README.markdown @@ -1,13 +1,13 @@ -bifunctors -========== - -[![Hackage](https://img.shields.io/hackage/v/bifunctors.svg)](https://hackage.haskell.org/package/bifunctors) [![Build Status](https://github.com/ekmett/bifunctors/workflows/Haskell-CI/badge.svg)](https://github.com/ekmett/bifunctors/actions?query=workflow%3AHaskell-CI) - -Contact Information -------------------- - -Contributions and bug reports are welcome! - -Please feel free to contact me through github or on the #haskell IRC channel on irc.freenode.net. - --Edward Kmett +bifunctors +========== + +[![Hackage](https://img.shields.io/hackage/v/bifunctors.svg)](https://hackage.haskell.org/package/bifunctors) [![Build Status](https://github.com/ekmett/bifunctors/workflows/Haskell-CI/badge.svg)](https://github.com/ekmett/bifunctors/actions?query=workflow%3AHaskell-CI) + +Contact Information +------------------- + +Contributions and bug reports are welcome! + +Please feel free to contact me through github or on the #haskell IRC channel on irc.freenode.net. + +-Edward Kmett diff --git a/Setup.lhs b/Setup.lhs --- a/Setup.lhs +++ b/Setup.lhs @@ -1,7 +1,7 @@ -#!/usr/bin/runhaskell -> module Main (main) where - -> import Distribution.Simple - -> main :: IO () -> main = defaultMain +#!/usr/bin/runhaskell +> module Main (main) where + +> import Distribution.Simple + +> main :: IO () +> main = defaultMain diff --git a/bifunctors.cabal b/bifunctors.cabal --- a/bifunctors.cabal +++ b/bifunctors.cabal @@ -1,139 +1,139 @@ -name: bifunctors -category: Data, Functors -version: 5.5.13 -license: BSD3 -cabal-version: >= 1.10 -license-file: LICENSE -author: Edward A. Kmett -maintainer: Edward A. Kmett -stability: provisional -homepage: http://github.com/ekmett/bifunctors/ -bug-reports: http://github.com/ekmett/bifunctors/issues -copyright: Copyright (C) 2008-2016 Edward A. Kmett -synopsis: Bifunctors -description: Bifunctors. -build-type: Simple -tested-with: GHC == 7.0.4 - , GHC == 7.2.2 - , GHC == 7.4.2 - , GHC == 7.6.3 - , GHC == 7.8.4 - , GHC == 7.10.3 - , GHC == 8.0.2 - , GHC == 8.2.2 - , GHC == 8.4.4 - , GHC == 8.6.5 - , GHC == 8.8.4 - , GHC == 8.10.7 - , GHC == 9.0.2 - , GHC == 9.2.2 -extra-source-files: - CHANGELOG.markdown - README.markdown - include/bifunctors-common.h - -source-repository head - type: git - location: https://github.com/ekmett/bifunctors.git - -flag semigroups - default: True - manual: True - description: - You can disable the use of the `semigroups` package using `-f-semigroups`. - . - Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. - -flag tagged - default: True - manual: True - description: - You can disable the use of the `tagged` package using `-f-tagged`. - . - Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. - -library - hs-source-dirs: src - include-dirs: include - includes: bifunctors-common.h - build-depends: - base >= 4.3 && < 5, - base-orphans >= 0.8.4 && < 1, - comonad >= 5.0.7 && < 6, - containers >= 0.2 && < 0.7, - template-haskell >= 2.4 && < 2.20, - th-abstraction >= 0.4.2.0 && < 0.5, - transformers >= 0.3 && < 0.7 - - if !impl(ghc > 8.2) - build-depends: transformers-compat >= 0.5 && < 0.8 - - if !impl(ghc >= 8.0) - build-depends: fail == 4.9.* - - if flag(tagged) - build-depends: tagged >= 0.8.6 && < 1 - - if flag(semigroups) && !impl(ghc >= 8.0) - build-depends: semigroups >= 0.18.5 && < 1 - - if impl(ghc<7.9) - hs-source-dirs: old-src/ghc709 - exposed-modules: Data.Bifunctor - - if impl(ghc<8.1) - hs-source-dirs: old-src/ghc801 - exposed-modules: - Data.Bifoldable - Data.Bitraversable - - if impl(ghc>=7.2) && impl(ghc<7.5) - build-depends: ghc-prim == 0.2.0.0 - - exposed-modules: - Data.Biapplicative - Data.Bifunctor.Biap - Data.Bifunctor.Biff - Data.Bifunctor.Clown - Data.Bifunctor.Fix - Data.Bifunctor.Flip - Data.Bifunctor.Functor - Data.Bifunctor.Join - Data.Bifunctor.Joker - Data.Bifunctor.Product - Data.Bifunctor.Sum - Data.Bifunctor.Tannen - Data.Bifunctor.TH - Data.Bifunctor.Wrapped - - other-modules: - Data.Bifunctor.TH.Internal - Paths_bifunctors - - ghc-options: -Wall - default-language: Haskell2010 - - if impl(ghc >= 9.0) - -- these flags may abort compilation with GHC-8.10 - -- https://gitlab.haskell.org/ghc/ghc/-/merge_requests/3295 - ghc-options: -Winferred-safe-imports -Wmissing-safe-haskell-mode - -test-suite bifunctors-spec - type: exitcode-stdio-1.0 - hs-source-dirs: tests - main-is: Spec.hs - other-modules: BifunctorSpec T89Spec - ghc-options: -Wall - if impl(ghc >= 8.6) - ghc-options: -Wno-star-is-type - default-language: Haskell2010 - build-tool-depends: hspec-discover:hspec-discover >= 1.8 - build-depends: - base >= 4 && < 5, - bifunctors, - hspec >= 1.8, - QuickCheck >= 2 && < 3, - template-haskell, - transformers, - transformers-compat - +name: bifunctors +category: Data, Functors +version: 5.5.14 +license: BSD3 +cabal-version: >= 1.10 +license-file: LICENSE +author: Edward A. Kmett +maintainer: Edward A. Kmett +stability: provisional +homepage: http://github.com/ekmett/bifunctors/ +bug-reports: http://github.com/ekmett/bifunctors/issues +copyright: Copyright (C) 2008-2016 Edward A. Kmett +synopsis: Bifunctors +description: Bifunctors. +build-type: Simple +tested-with: GHC == 7.0.4 + , GHC == 7.2.2 + , GHC == 7.4.2 + , GHC == 7.6.3 + , GHC == 7.8.4 + , GHC == 7.10.3 + , GHC == 8.0.2 + , GHC == 8.2.2 + , GHC == 8.4.4 + , GHC == 8.6.5 + , GHC == 8.8.4 + , GHC == 8.10.7 + , GHC == 9.0.2 + , GHC == 9.2.2 +extra-source-files: + CHANGELOG.markdown + README.markdown + include/bifunctors-common.h + +source-repository head + type: git + location: https://github.com/ekmett/bifunctors.git + +flag semigroups + default: True + manual: True + description: + You can disable the use of the `semigroups` package using `-f-semigroups`. + . + Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. + +flag tagged + default: True + manual: True + description: + You can disable the use of the `tagged` package using `-f-tagged`. + . + Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. + +library + hs-source-dirs: src + include-dirs: include + includes: bifunctors-common.h + build-depends: + base >= 4.3 && < 5, + base-orphans >= 0.8.4 && < 1, + comonad >= 5.0.7 && < 6, + containers >= 0.2 && < 0.7, + template-haskell >= 2.4 && < 2.20, + th-abstraction >= 0.4.2.0 && < 0.5, + transformers >= 0.3 && < 0.7 + + if !impl(ghc > 8.2) + build-depends: transformers-compat >= 0.5 && < 0.8 + + if !impl(ghc >= 8.0) + build-depends: fail == 4.9.* + + if flag(tagged) + build-depends: tagged >= 0.8.6 && < 1 + + if flag(semigroups) && !impl(ghc >= 8.0) + build-depends: semigroups >= 0.18.5 && < 1 + + if impl(ghc<7.9) + hs-source-dirs: old-src/ghc709 + exposed-modules: Data.Bifunctor + + if impl(ghc<8.1) + hs-source-dirs: old-src/ghc801 + exposed-modules: + Data.Bifoldable + Data.Bitraversable + + if impl(ghc>=7.2) && impl(ghc<7.5) + build-depends: ghc-prim == 0.2.0.0 + + exposed-modules: + Data.Biapplicative + Data.Bifunctor.Biap + Data.Bifunctor.Biff + Data.Bifunctor.Clown + Data.Bifunctor.Fix + Data.Bifunctor.Flip + Data.Bifunctor.Functor + Data.Bifunctor.Join + Data.Bifunctor.Joker + Data.Bifunctor.Product + Data.Bifunctor.Sum + Data.Bifunctor.Tannen + Data.Bifunctor.TH + Data.Bifunctor.Wrapped + + other-modules: + Data.Bifunctor.TH.Internal + Paths_bifunctors + + ghc-options: -Wall + default-language: Haskell2010 + + if impl(ghc >= 9.0) + -- these flags may abort compilation with GHC-8.10 + -- https://gitlab.haskell.org/ghc/ghc/-/merge_requests/3295 + ghc-options: -Winferred-safe-imports -Wmissing-safe-haskell-mode + +test-suite bifunctors-spec + type: exitcode-stdio-1.0 + hs-source-dirs: tests + main-is: Spec.hs + other-modules: BifunctorSpec T89Spec + ghc-options: -Wall + if impl(ghc >= 8.6) + ghc-options: -Wno-star-is-type + default-language: Haskell2010 + build-tool-depends: hspec-discover:hspec-discover >= 1.8 + build-depends: + base >= 4 && < 5, + bifunctors, + hspec >= 1.8, + QuickCheck >= 2 && < 3, + template-haskell, + transformers, + transformers-compat + diff --git a/include/bifunctors-common.h b/include/bifunctors-common.h --- a/include/bifunctors-common.h +++ b/include/bifunctors-common.h @@ -1,19 +1,19 @@ -#ifndef MIN_VERSION_base -#define MIN_VERSION_base(x,y,z) 1 -#endif - -#ifndef MIN_VERSION_transformers_compat -#define MIN_VERSION_transformers_compat(x,y,z) 0 -#endif - -#if MIN_VERSION_base(4,9,0) -#define LIFTED_FUNCTOR_CLASSES 1 -#else -#if MIN_VERSION_transformers(0,5,0) -#define LIFTED_FUNCTOR_CLASSES 1 -#else -#if MIN_VERSION_transformers_compat(0,5,0) && !MIN_VERSION_transformers(0,4,0) -#define LIFTED_FUNCTOR_CLASSES 1 -#endif -#endif -#endif +#ifndef MIN_VERSION_base +#define MIN_VERSION_base(x,y,z) 1 +#endif + +#ifndef MIN_VERSION_transformers_compat +#define MIN_VERSION_transformers_compat(x,y,z) 0 +#endif + +#if MIN_VERSION_base(4,9,0) +#define LIFTED_FUNCTOR_CLASSES 1 +#else +#if MIN_VERSION_transformers(0,5,0) +#define LIFTED_FUNCTOR_CLASSES 1 +#else +#if MIN_VERSION_transformers_compat(0,5,0) && !MIN_VERSION_transformers(0,4,0) +#define LIFTED_FUNCTOR_CLASSES 1 +#endif +#endif +#endif diff --git a/old-src/ghc709/Data/Bifunctor.hs b/old-src/ghc709/Data/Bifunctor.hs --- a/old-src/ghc709/Data/Bifunctor.hs +++ b/old-src/ghc709/Data/Bifunctor.hs @@ -1,185 +1,185 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE StandaloneDeriving #-} - -#if __GLASGOW_HASKELL__ >= 704 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2008-2015 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bifunctor - ( -- * Overview - -- - -- Bifunctors extend the standard 'Functor' to two arguments - - -- * Examples - -- $examples - Bifunctor(..) - ) where - -import Control.Applicative -import Data.Functor.Constant -import Data.Semigroup - -#ifdef MIN_VERSION_tagged -import Data.Tagged -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics (K1(..)) -#endif - -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif - --- | Minimal definition either 'bimap' or 'first' and 'second' - --- | Formally, the class 'Bifunctor' represents a bifunctor --- from @Hask@ -> @Hask@. --- --- Intuitively it is a bifunctor where both the first and second arguments are covariant. --- --- You can define a 'Bifunctor' by either defining 'bimap' or by defining both --- 'first' and 'second'. --- --- If you supply 'bimap', you should ensure that: --- --- @'bimap' 'id' 'id' ≡ 'id'@ --- --- If you supply 'first' and 'second', ensure: --- --- @ --- 'first' 'id' ≡ 'id' --- 'second' 'id' ≡ 'id' --- @ --- --- If you supply both, you should also ensure: --- --- @'bimap' f g ≡ 'first' f '.' 'second' g@ --- --- These ensure by parametricity: --- --- @ --- 'bimap' (f '.' g) (h '.' i) ≡ 'bimap' f h '.' 'bimap' g i --- 'first' (f '.' g) ≡ 'first' f '.' 'first' g --- 'second' (f '.' g) ≡ 'second' f '.' 'second' g --- @ -class Bifunctor p where - -- | Map over both arguments at the same time. - -- - -- @'bimap' f g ≡ 'first' f '.' 'second' g@ - bimap :: (a -> b) -> (c -> d) -> p a c -> p b d - bimap f g = first f . second g - {-# INLINE bimap #-} - - -- | Map covariantly over the first argument. - -- - -- @'first' f ≡ 'bimap' f 'id'@ - first :: (a -> b) -> p a c -> p b c - first f = bimap f id - {-# INLINE first #-} - - -- | Map covariantly over the second argument. - -- - -- @'second' ≡ 'bimap' 'id'@ - second :: (b -> c) -> p a b -> p a c - second = bimap id - {-# INLINE second #-} - -#if __GLASGOW_HASKELL__ >= 708 - {-# MINIMAL bimap | first, second #-} -#endif - -#if __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 710 -deriving instance Typeable Bifunctor -#endif - -instance Bifunctor (,) where - bimap f g ~(a, b) = (f a, g b) - {-# INLINE bimap #-} - -instance Bifunctor Arg where - bimap f g (Arg a b) = Arg (f a) (g b) - -instance Bifunctor ((,,) x) where - bimap f g ~(x, a, b) = (x, f a, g b) - {-# INLINE bimap #-} - -instance Bifunctor ((,,,) x y) where - bimap f g ~(x, y, a, b) = (x, y, f a, g b) - {-# INLINE bimap #-} - -instance Bifunctor ((,,,,) x y z) where - bimap f g ~(x, y, z, a, b) = (x, y, z, f a, g b) - {-# INLINE bimap #-} - -instance Bifunctor ((,,,,,) x y z w) where - bimap f g ~(x, y, z, w, a, b) = (x, y, z, w, f a, g b) - {-# INLINE bimap #-} - -instance Bifunctor ((,,,,,,) x y z w v) where - bimap f g ~(x, y, z, w, v, a, b) = (x, y, z, w, v, f a, g b) - {-# INLINE bimap #-} - -instance Bifunctor Either where - bimap f _ (Left a) = Left (f a) - bimap _ g (Right b) = Right (g b) - {-# INLINE bimap #-} - -instance Bifunctor Const where - bimap f _ (Const a) = Const (f a) - {-# INLINE bimap #-} - -instance Bifunctor Constant where - bimap f _ (Constant a) = Constant (f a) - {-# INLINE bimap #-} - -#if __GLASGOW_HASKELL__ >= 702 -instance Bifunctor (K1 i) where - bimap f _ (K1 c) = K1 (f c) - {-# INLINE bimap #-} -#endif - -#ifdef MIN_VERSION_tagged -instance Bifunctor Tagged where - bimap _ g (Tagged b) = Tagged (g b) - {-# INLINE bimap #-} -#endif - --- $examples --- --- ==== __Examples__ --- --- While the standard 'Functor' instance for 'Either' is limited to mapping over 'Right' arguments, --- the 'Bifunctor' instance allows mapping over the 'Left', 'Right', or both arguments: --- --- > let x = Left "foo" :: Either String Integer --- --- In the case of 'first' and 'second', the function may or may not be applied: --- --- > first (++ "bar") x == Left "foobar" --- > second (+2) x == Left "foo" --- --- In the case of 'bimap', only one of the functions will be applied: --- --- > bimap (++ "bar") (+2) x == Left "foobar" --- --- The 'Bifunctor' instance for 2 element tuples allows mapping over one or both of the elements: --- --- > let x = ("foo",1) --- > --- > first (++ "bar") x == ("foobar", 1) --- > second (+2) x == ("foo", 3) --- > bimap (++ "bar") (+2) x == ("foobar", 3) +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE StandaloneDeriving #-} + +#if __GLASGOW_HASKELL__ >= 704 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2008-2015 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +---------------------------------------------------------------------------- +module Data.Bifunctor + ( -- * Overview + -- + -- Bifunctors extend the standard 'Functor' to two arguments + + -- * Examples + -- $examples + Bifunctor(..) + ) where + +import Control.Applicative +import Data.Functor.Constant +import Data.Semigroup + +#ifdef MIN_VERSION_tagged +import Data.Tagged +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics (K1(..)) +#endif + +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif + +-- | Minimal definition either 'bimap' or 'first' and 'second' + +-- | Formally, the class 'Bifunctor' represents a bifunctor +-- from @Hask@ -> @Hask@. +-- +-- Intuitively it is a bifunctor where both the first and second arguments are covariant. +-- +-- You can define a 'Bifunctor' by either defining 'bimap' or by defining both +-- 'first' and 'second'. +-- +-- If you supply 'bimap', you should ensure that: +-- +-- @'bimap' 'id' 'id' ≡ 'id'@ +-- +-- If you supply 'first' and 'second', ensure: +-- +-- @ +-- 'first' 'id' ≡ 'id' +-- 'second' 'id' ≡ 'id' +-- @ +-- +-- If you supply both, you should also ensure: +-- +-- @'bimap' f g ≡ 'first' f '.' 'second' g@ +-- +-- These ensure by parametricity: +-- +-- @ +-- 'bimap' (f '.' g) (h '.' i) ≡ 'bimap' f h '.' 'bimap' g i +-- 'first' (f '.' g) ≡ 'first' f '.' 'first' g +-- 'second' (f '.' g) ≡ 'second' f '.' 'second' g +-- @ +class Bifunctor p where + -- | Map over both arguments at the same time. + -- + -- @'bimap' f g ≡ 'first' f '.' 'second' g@ + bimap :: (a -> b) -> (c -> d) -> p a c -> p b d + bimap f g = first f . second g + {-# INLINE bimap #-} + + -- | Map covariantly over the first argument. + -- + -- @'first' f ≡ 'bimap' f 'id'@ + first :: (a -> b) -> p a c -> p b c + first f = bimap f id + {-# INLINE first #-} + + -- | Map covariantly over the second argument. + -- + -- @'second' ≡ 'bimap' 'id'@ + second :: (b -> c) -> p a b -> p a c + second = bimap id + {-# INLINE second #-} + +#if __GLASGOW_HASKELL__ >= 708 + {-# MINIMAL bimap | first, second #-} +#endif + +#if __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 710 +deriving instance Typeable Bifunctor +#endif + +instance Bifunctor (,) where + bimap f g ~(a, b) = (f a, g b) + {-# INLINE bimap #-} + +instance Bifunctor Arg where + bimap f g (Arg a b) = Arg (f a) (g b) + +instance Bifunctor ((,,) x) where + bimap f g ~(x, a, b) = (x, f a, g b) + {-# INLINE bimap #-} + +instance Bifunctor ((,,,) x y) where + bimap f g ~(x, y, a, b) = (x, y, f a, g b) + {-# INLINE bimap #-} + +instance Bifunctor ((,,,,) x y z) where + bimap f g ~(x, y, z, a, b) = (x, y, z, f a, g b) + {-# INLINE bimap #-} + +instance Bifunctor ((,,,,,) x y z w) where + bimap f g ~(x, y, z, w, a, b) = (x, y, z, w, f a, g b) + {-# INLINE bimap #-} + +instance Bifunctor ((,,,,,,) x y z w v) where + bimap f g ~(x, y, z, w, v, a, b) = (x, y, z, w, v, f a, g b) + {-# INLINE bimap #-} + +instance Bifunctor Either where + bimap f _ (Left a) = Left (f a) + bimap _ g (Right b) = Right (g b) + {-# INLINE bimap #-} + +instance Bifunctor Const where + bimap f _ (Const a) = Const (f a) + {-# INLINE bimap #-} + +instance Bifunctor Constant where + bimap f _ (Constant a) = Constant (f a) + {-# INLINE bimap #-} + +#if __GLASGOW_HASKELL__ >= 702 +instance Bifunctor (K1 i) where + bimap f _ (K1 c) = K1 (f c) + {-# INLINE bimap #-} +#endif + +#ifdef MIN_VERSION_tagged +instance Bifunctor Tagged where + bimap _ g (Tagged b) = Tagged (g b) + {-# INLINE bimap #-} +#endif + +-- $examples +-- +-- ==== __Examples__ +-- +-- While the standard 'Functor' instance for 'Either' is limited to mapping over 'Right' arguments, +-- the 'Bifunctor' instance allows mapping over the 'Left', 'Right', or both arguments: +-- +-- > let x = Left "foo" :: Either String Integer +-- +-- In the case of 'first' and 'second', the function may or may not be applied: +-- +-- > first (++ "bar") x == Left "foobar" +-- > second (+2) x == Left "foo" +-- +-- In the case of 'bimap', only one of the functions will be applied: +-- +-- > bimap (++ "bar") (+2) x == Left "foobar" +-- +-- The 'Bifunctor' instance for 2 element tuples allows mapping over one or both of the elements: +-- +-- > let x = ("foo",1) +-- > +-- > first (++ "bar") x == ("foobar", 1) +-- > second (+2) x == ("foo", 3) +-- > bimap (++ "bar") (+2) x == ("foobar", 3) diff --git a/old-src/ghc801/Data/Bifoldable.hs b/old-src/ghc801/Data/Bifoldable.hs --- a/old-src/ghc801/Data/Bifoldable.hs +++ b/old-src/ghc801/Data/Bifoldable.hs @@ -1,487 +1,487 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE ScopedTypeVariables #-} -{-# LANGUAGE StandaloneDeriving #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2011-2015 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bifoldable - ( Bifoldable(..) - , bifoldr' - , bifoldr1 - , bifoldrM - , bifoldl' - , bifoldl1 - , bifoldlM - , bitraverse_ - , bifor_ - , bimapM_ - , biforM_ - , bimsum - , bisequenceA_ - , bisequence_ - , biasum - , biList - , binull - , bilength - , bielem - , bimaximum - , biminimum - , bisum - , biproduct - , biconcat - , biconcatMap - , biand - , bior - , biany - , biall - , bimaximumBy - , biminimumBy - , binotElem - , bifind - ) where - -import Control.Applicative -import Control.Monad -import Data.Functor.Constant -import Data.Maybe (fromMaybe) -import Data.Monoid - -#if MIN_VERSION_base(4,7,0) -import Data.Coerce -#else -import Unsafe.Coerce -#endif - -import Data.Semigroup (Arg(..)) - -#ifdef MIN_VERSION_tagged -import Data.Tagged -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics (K1(..)) -#endif - -#if __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 710 -import Data.Typeable -#endif - --- | 'Bifoldable' identifies foldable structures with two different varieties --- of elements (as opposed to 'Foldable', which has one variety of element). --- Common examples are 'Either' and '(,)': --- --- > instance Bifoldable Either where --- > bifoldMap f _ (Left a) = f a --- > bifoldMap _ g (Right b) = g b --- > --- > instance Bifoldable (,) where --- > bifoldr f g z (a, b) = f a (g b z) --- --- A minimal 'Bifoldable' definition consists of either 'bifoldMap' or --- 'bifoldr'. When defining more than this minimal set, one should ensure --- that the following identities hold: --- --- @ --- 'bifold' ≡ 'bifoldMap' 'id' 'id' --- 'bifoldMap' f g ≡ 'bifoldr' ('mappend' . f) ('mappend' . g) 'mempty' --- 'bifoldr' f g z t ≡ 'appEndo' ('bifoldMap' (Endo . f) (Endo . g) t) z --- @ --- --- If the type is also a 'Bifunctor' instance, it should satisfy: --- --- > 'bifoldMap' f g ≡ 'bifold' . 'bimap' f g --- --- which implies that --- --- > 'bifoldMap' f g . 'bimap' h i ≡ 'bifoldMap' (f . h) (g . i) -class Bifoldable p where - -- | Combines the elements of a structure using a monoid. - -- - -- @'bifold' ≡ 'bifoldMap' 'id' 'id'@ - bifold :: Monoid m => p m m -> m - bifold = bifoldMap id id - {-# INLINE bifold #-} - - -- | Combines the elements of a structure, given ways of mapping them to a - -- common monoid. - -- - -- @'bifoldMap' f g ≡ 'bifoldr' ('mappend' . f) ('mappend' . g) 'mempty'@ - bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> p a b -> m - bifoldMap f g = bifoldr (mappend . f) (mappend . g) mempty - {-# INLINE bifoldMap #-} - - -- | Combines the elements of a structure in a right associative manner. Given - -- a hypothetical function @toEitherList :: p a b -> [Either a b]@ yielding a - -- list of all elements of a structure in order, the following would hold: - -- - -- @'bifoldr' f g z ≡ 'foldr' ('either' f g) z . toEitherList@ - bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> p a b -> c - bifoldr f g z t = appEndo (bifoldMap (Endo #. f) (Endo #. g) t) z - {-# INLINE bifoldr #-} - - -- | Combines the elments of a structure in a left associative manner. Given a - -- hypothetical function @toEitherList :: p a b -> [Either a b]@ yielding a - -- list of all elements of a structure in order, the following would hold: - -- - -- @'bifoldl' f g z ≡ 'foldl' (\acc -> 'either' (f acc) (g acc)) z . toEitherList@ - -- - -- Note that if you want an efficient left-fold, you probably want to use - -- 'bifoldl'' instead of 'bifoldl'. The reason is that the latter does not - -- force the "inner" results, resulting in a thunk chain which then must be - -- evaluated from the outside-in. - bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> p a b -> c - bifoldl f g z t = appEndo (getDual (bifoldMap (Dual . Endo . flip f) (Dual . Endo . flip g) t)) z - {-# INLINE bifoldl #-} - -#if __GLASGOW_HASKELL__ >= 708 - {-# MINIMAL bifoldr | bifoldMap #-} -#endif - -#if __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 710 -deriving instance Typeable Bifoldable -#endif - -instance Bifoldable Arg where - bifoldMap f g (Arg a b) = f a `mappend` g b - -instance Bifoldable (,) where - bifoldMap f g ~(a, b) = f a `mappend` g b - {-# INLINE bifoldMap #-} - -instance Bifoldable Const where - bifoldMap f _ (Const a) = f a - {-# INLINE bifoldMap #-} - -instance Bifoldable Constant where - bifoldMap f _ (Constant a) = f a - {-# INLINE bifoldMap #-} - -#if __GLASGOW_HASKELL__ >= 702 -instance Bifoldable (K1 i) where - bifoldMap f _ (K1 c) = f c - {-# INLINE bifoldMap #-} -#endif - -instance Bifoldable ((,,) x) where - bifoldMap f g ~(_,a,b) = f a `mappend` g b - {-# INLINE bifoldMap #-} - -instance Bifoldable ((,,,) x y) where - bifoldMap f g ~(_,_,a,b) = f a `mappend` g b - {-# INLINE bifoldMap #-} - -instance Bifoldable ((,,,,) x y z) where - bifoldMap f g ~(_,_,_,a,b) = f a `mappend` g b - {-# INLINE bifoldMap #-} - -instance Bifoldable ((,,,,,) x y z w) where - bifoldMap f g ~(_,_,_,_,a,b) = f a `mappend` g b - {-# INLINE bifoldMap #-} - -instance Bifoldable ((,,,,,,) x y z w v) where - bifoldMap f g ~(_,_,_,_,_,a,b) = f a `mappend` g b - {-# INLINE bifoldMap #-} - -#ifdef MIN_VERSION_tagged -instance Bifoldable Tagged where - bifoldMap _ g (Tagged b) = g b - {-# INLINE bifoldMap #-} -#endif - -instance Bifoldable Either where - bifoldMap f _ (Left a) = f a - bifoldMap _ g (Right b) = g b - {-# INLINE bifoldMap #-} - --- | As 'bifoldr', but strict in the result of the reduction functions at each --- step. -bifoldr' :: Bifoldable t => (a -> c -> c) -> (b -> c -> c) -> c -> t a b -> c -bifoldr' f g z0 xs = bifoldl f' g' id xs z0 where - f' k x z = k $! f x z - g' k x z = k $! g x z -{-# INLINE bifoldr' #-} - --- | A variant of 'bifoldr' that has no base case, --- and thus may only be applied to non-empty structures. -bifoldr1 :: Bifoldable t => (a -> a -> a) -> t a a -> a -bifoldr1 f xs = fromMaybe (error "bifoldr1: empty structure") - (bifoldr mbf mbf Nothing xs) - where - mbf x m = Just (case m of - Nothing -> x - Just y -> f x y) -{-# INLINE bifoldr1 #-} - --- | Right associative monadic bifold over a structure. -bifoldrM :: (Bifoldable t, Monad m) => (a -> c -> m c) -> (b -> c -> m c) -> c -> t a b -> m c -bifoldrM f g z0 xs = bifoldl f' g' return xs z0 where - f' k x z = f x z >>= k - g' k x z = g x z >>= k -{-# INLINE bifoldrM #-} - --- | As 'bifoldl', but strict in the result of the reduction functions at each --- step. --- --- This ensures that each step of the bifold is forced to weak head normal form --- before being applied, avoiding the collection of thunks that would otherwise --- occur. This is often what you want to strictly reduce a finite structure to --- a single, monolithic result (e.g., 'bilength'). -bifoldl':: Bifoldable t => (a -> b -> a) -> (a -> c -> a) -> a -> t b c -> a -bifoldl' f g z0 xs = bifoldr f' g' id xs z0 where - f' x k z = k $! f z x - g' x k z = k $! g z x -{-# INLINE bifoldl' #-} - --- | A variant of 'bifoldl' that has no base case, --- and thus may only be applied to non-empty structures. -bifoldl1 :: Bifoldable t => (a -> a -> a) -> t a a -> a -bifoldl1 f xs = fromMaybe (error "bifoldl1: empty structure") - (bifoldl mbf mbf Nothing xs) - where - mbf m y = Just (case m of - Nothing -> y - Just x -> f x y) -{-# INLINe bifoldl1 #-} - --- | Left associative monadic bifold over a structure. -bifoldlM :: (Bifoldable t, Monad m) => (a -> b -> m a) -> (a -> c -> m a) -> a -> t b c -> m a -bifoldlM f g z0 xs = bifoldr f' g' return xs z0 where - f' x k z = f z x >>= k - g' x k z = g z x >>= k -{-# INLINE bifoldlM #-} - --- | Map each element of a structure using one of two actions, evaluate these --- actions from left to right, and ignore the results. For a version that --- doesn't ignore the results, see 'Data.Bitraversable.bitraverse'. -bitraverse_ :: (Bifoldable t, Applicative f) => (a -> f c) -> (b -> f d) -> t a b -> f () -bitraverse_ f g = bifoldr ((*>) . f) ((*>) . g) (pure ()) -{-# INLINE bitraverse_ #-} - --- | As 'bitraverse_', but with the structure as the primary argument. For a --- version that doesn't ignore the results, see 'Data.Bitraversable.bifor'. --- --- >>> > bifor_ ('a', "bc") print (print . reverse) --- 'a' --- "cb" -bifor_ :: (Bifoldable t, Applicative f) => t a b -> (a -> f c) -> (b -> f d) -> f () -bifor_ t f g = bitraverse_ f g t -{-# INLINE bifor_ #-} - --- | As 'Data.Bitraversable.bimapM', but ignores the results of the functions, --- merely performing the "actions". -bimapM_:: (Bifoldable t, Monad m) => (a -> m c) -> (b -> m d) -> t a b -> m () -bimapM_ f g = bifoldr ((>>) . f) ((>>) . g) (return ()) -{-# INLINE bimapM_ #-} - --- | As 'bimapM_', but with the structure as the primary argument. -biforM_ :: (Bifoldable t, Monad m) => t a b -> (a -> m c) -> (b -> m d) -> m () -biforM_ t f g = bimapM_ f g t -{-# INLINE biforM_ #-} - --- | As 'Data.Bitraversable.bisequenceA', but ignores the results of the actions. -bisequenceA_ :: (Bifoldable t, Applicative f) => t (f a) (f b) -> f () -bisequenceA_ = bifoldr (*>) (*>) (pure ()) -{-# INLINE bisequenceA_ #-} - --- | Evaluate each action in the structure from left to right, and ignore the --- results. For a version that doesn't ignore the results, see --- 'Data.Bitraversable.bisequence'. -bisequence_ :: (Bifoldable t, Monad m) => t (m a) (m b) -> m () -bisequence_ = bifoldr (>>) (>>) (return ()) -{-# INLINE bisequence_ #-} - --- | The sum of a collection of actions, generalizing 'biconcat'. -biasum :: (Bifoldable t, Alternative f) => t (f a) (f a) -> f a -biasum = bifoldr (<|>) (<|>) empty -{-# INLINE biasum #-} - --- | The sum of a collection of actions, generalizing 'biconcat'. -bimsum :: (Bifoldable t, MonadPlus m) => t (m a) (m a) -> m a -bimsum = bifoldr mplus mplus mzero -{-# INLINE bimsum #-} - --- | Collects the list of elements of a structure, from left to right. -biList :: Bifoldable t => t a a -> [a] -biList = bifoldr (:) (:) [] -{-# INLINE biList #-} - --- | Test whether the structure is empty. -binull :: Bifoldable t => t a b -> Bool -binull = bifoldr (\_ _ -> False) (\_ _ -> False) True -{-# INLINE binull #-} - --- | Returns the size/length of a finite structure as an 'Int'. -bilength :: Bifoldable t => t a b -> Int -bilength = bifoldl' (\c _ -> c+1) (\c _ -> c+1) 0 -{-# INLINE bilength #-} - --- | Does the element occur in the structure? -bielem :: (Bifoldable t, Eq a) => a -> t a a -> Bool -bielem x = biany (== x) (== x) -{-# INLINE bielem #-} - --- | Reduces a structure of lists to the concatenation of those lists. -biconcat :: Bifoldable t => t [a] [a] -> [a] -biconcat = bifold -{-# INLINE biconcat #-} - -newtype Max a = Max {getMax :: Maybe a} -newtype Min a = Min {getMin :: Maybe a} - -instance Ord a => Monoid (Max a) where - mempty = Max Nothing - - {-# INLINE mappend #-} - m `mappend` Max Nothing = m - Max Nothing `mappend` n = n - (Max m@(Just x)) `mappend` (Max n@(Just y)) - | x >= y = Max m - | otherwise = Max n - -instance Ord a => Monoid (Min a) where - mempty = Min Nothing - - {-# INLINE mappend #-} - m `mappend` Min Nothing = m - Min Nothing `mappend` n = n - (Min m@(Just x)) `mappend` (Min n@(Just y)) - | x <= y = Min m - | otherwise = Min n - --- | The largest element of a non-empty structure. -bimaximum :: forall t a. (Bifoldable t, Ord a) => t a a -> a -bimaximum = fromMaybe (error "bimaximum: empty structure") . - getMax . bifoldMap mj mj - where mj = Max #. (Just :: a -> Maybe a) -{-# INLINE bimaximum #-} - --- | The least element of a non-empty structure. -biminimum :: forall t a. (Bifoldable t, Ord a) => t a a -> a -biminimum = fromMaybe (error "biminimum: empty structure") . - getMin . bifoldMap mj mj - where mj = Min #. (Just :: a -> Maybe a) -{-# INLINE biminimum #-} - --- | The 'bisum' function computes the sum of the numbers of a structure. -bisum :: (Bifoldable t, Num a) => t a a -> a -bisum = getSum #. bifoldMap Sum Sum -{-# INLINE bisum #-} - --- | The 'biproduct' function computes the product of the numbers of a --- structure. -biproduct :: (Bifoldable t, Num a) => t a a -> a -biproduct = getProduct #. bifoldMap Product Product -{-# INLINE biproduct #-} - --- | Given a means of mapping the elements of a structure to lists, computes the --- concatenation of all such lists in order. -biconcatMap :: Bifoldable t => (a -> [c]) -> (b -> [c]) -> t a b -> [c] -biconcatMap = bifoldMap -{-# INLINE biconcatMap #-} - --- | 'biand' returns the conjunction of a container of Bools. For the --- result to be 'True', the container must be finite; 'False', however, --- results from a 'False' value finitely far from the left end. -biand :: Bifoldable t => t Bool Bool -> Bool -biand = getAll #. bifoldMap All All -{-# INLINE biand #-} - --- | 'bior' returns the disjunction of a container of Bools. For the --- result to be 'False', the container must be finite; 'True', however, --- results from a 'True' value finitely far from the left end. -bior :: Bifoldable t => t Bool Bool -> Bool -bior = getAny #. bifoldMap Any Any -{-# INLINE bior #-} - --- | Determines whether any element of the structure satisfies the appropriate --- predicate. -biany :: Bifoldable t => (a -> Bool) -> (b -> Bool) -> t a b -> Bool -biany p q = getAny #. bifoldMap (Any . p) (Any . q) -{-# INLINE biany #-} - --- | Determines whether all elements of the structure satisfy the appropriate --- predicate. -biall :: Bifoldable t => (a -> Bool) -> (b -> Bool) -> t a b -> Bool -biall p q = getAll #. bifoldMap (All . p) (All . q) -{-# INLINE biall #-} - --- | The largest element of a non-empty structure with respect to the --- given comparison function. -bimaximumBy :: Bifoldable t => (a -> a -> Ordering) -> t a a -> a -bimaximumBy cmp = bifoldr1 max' - where max' x y = case cmp x y of - GT -> x - _ -> y -{-# INLINE bimaximumBy #-} - --- | The least element of a non-empty structure with respect to the --- given comparison function. -biminimumBy :: Bifoldable t => (a -> a -> Ordering) -> t a a -> a -biminimumBy cmp = bifoldr1 min' - where min' x y = case cmp x y of - GT -> y - _ -> x -{-# INLINE biminimumBy #-} - --- | 'binotElem' is the negation of 'bielem'. -binotElem :: (Bifoldable t, Eq a) => a -> t a a-> Bool -binotElem x = not . bielem x -{-# INLINE binotElem #-} - --- | The 'bifind' function takes a predicate and a structure and returns --- the leftmost element of the structure matching the predicate, or --- 'Nothing' if there is no such element. -bifind :: Bifoldable t => (a -> Bool) -> t a a -> Maybe a -bifind p = getFirst . bifoldMap finder finder - where finder x = First (if p x then Just x else Nothing) -{-# INLINE bifind #-} - --- See Note [Function coercion] -#if MIN_VERSION_base(4,7,0) -(#.) :: Coercible b c => (b -> c) -> (a -> b) -> (a -> c) -(#.) _f = coerce -#else -(#.) :: (b -> c) -> (a -> b) -> (a -> c) -(#.) _f = unsafeCoerce -#endif -{-# INLINE (#.) #-} - -{- -Note [Function coercion] -~~~~~~~~~~~~~~~~~~~~~~~~ - -Several functions here use (#.) instead of (.) to avoid potential efficiency -problems relating to #7542. The problem, in a nutshell: - -If N is a newtype constructor, then N x will always have the same -representation as x (something similar applies for a newtype deconstructor). -However, if f is a function, - -N . f = \x -> N (f x) - -This looks almost the same as f, but the eta expansion lifts it--the lhs could -be _|_, but the rhs never is. This can lead to very inefficient code. Thus we -steal a technique from Shachaf and Edward Kmett and adapt it to the current -(rather clean) setting. Instead of using N . f, we use N .## f, which is -just - -coerce f `asTypeOf` (N . f) - -That is, we just *pretend* that f has the right type, and thanks to the safety -of coerce, the type checker guarantees that nothing really goes wrong. We still -have to be a bit careful, though: remember that #. completely ignores the -*value* of its left operand. --} +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# LANGUAGE StandaloneDeriving #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2011-2015 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +---------------------------------------------------------------------------- +module Data.Bifoldable + ( Bifoldable(..) + , bifoldr' + , bifoldr1 + , bifoldrM + , bifoldl' + , bifoldl1 + , bifoldlM + , bitraverse_ + , bifor_ + , bimapM_ + , biforM_ + , bimsum + , bisequenceA_ + , bisequence_ + , biasum + , biList + , binull + , bilength + , bielem + , bimaximum + , biminimum + , bisum + , biproduct + , biconcat + , biconcatMap + , biand + , bior + , biany + , biall + , bimaximumBy + , biminimumBy + , binotElem + , bifind + ) where + +import Control.Applicative +import Control.Monad +import Data.Functor.Constant +import Data.Maybe (fromMaybe) +import Data.Monoid + +#if MIN_VERSION_base(4,7,0) +import Data.Coerce +#else +import Unsafe.Coerce +#endif + +import Data.Semigroup (Arg(..)) + +#ifdef MIN_VERSION_tagged +import Data.Tagged +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics (K1(..)) +#endif + +#if __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 710 +import Data.Typeable +#endif + +-- | 'Bifoldable' identifies foldable structures with two different varieties +-- of elements (as opposed to 'Foldable', which has one variety of element). +-- Common examples are 'Either' and '(,)': +-- +-- > instance Bifoldable Either where +-- > bifoldMap f _ (Left a) = f a +-- > bifoldMap _ g (Right b) = g b +-- > +-- > instance Bifoldable (,) where +-- > bifoldr f g z (a, b) = f a (g b z) +-- +-- A minimal 'Bifoldable' definition consists of either 'bifoldMap' or +-- 'bifoldr'. When defining more than this minimal set, one should ensure +-- that the following identities hold: +-- +-- @ +-- 'bifold' ≡ 'bifoldMap' 'id' 'id' +-- 'bifoldMap' f g ≡ 'bifoldr' ('mappend' . f) ('mappend' . g) 'mempty' +-- 'bifoldr' f g z t ≡ 'appEndo' ('bifoldMap' (Endo . f) (Endo . g) t) z +-- @ +-- +-- If the type is also a 'Bifunctor' instance, it should satisfy: +-- +-- > 'bifoldMap' f g ≡ 'bifold' . 'bimap' f g +-- +-- which implies that +-- +-- > 'bifoldMap' f g . 'bimap' h i ≡ 'bifoldMap' (f . h) (g . i) +class Bifoldable p where + -- | Combines the elements of a structure using a monoid. + -- + -- @'bifold' ≡ 'bifoldMap' 'id' 'id'@ + bifold :: Monoid m => p m m -> m + bifold = bifoldMap id id + {-# INLINE bifold #-} + + -- | Combines the elements of a structure, given ways of mapping them to a + -- common monoid. + -- + -- @'bifoldMap' f g ≡ 'bifoldr' ('mappend' . f) ('mappend' . g) 'mempty'@ + bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> p a b -> m + bifoldMap f g = bifoldr (mappend . f) (mappend . g) mempty + {-# INLINE bifoldMap #-} + + -- | Combines the elements of a structure in a right associative manner. Given + -- a hypothetical function @toEitherList :: p a b -> [Either a b]@ yielding a + -- list of all elements of a structure in order, the following would hold: + -- + -- @'bifoldr' f g z ≡ 'foldr' ('either' f g) z . toEitherList@ + bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> p a b -> c + bifoldr f g z t = appEndo (bifoldMap (Endo #. f) (Endo #. g) t) z + {-# INLINE bifoldr #-} + + -- | Combines the elments of a structure in a left associative manner. Given a + -- hypothetical function @toEitherList :: p a b -> [Either a b]@ yielding a + -- list of all elements of a structure in order, the following would hold: + -- + -- @'bifoldl' f g z ≡ 'foldl' (\acc -> 'either' (f acc) (g acc)) z . toEitherList@ + -- + -- Note that if you want an efficient left-fold, you probably want to use + -- 'bifoldl'' instead of 'bifoldl'. The reason is that the latter does not + -- force the "inner" results, resulting in a thunk chain which then must be + -- evaluated from the outside-in. + bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> p a b -> c + bifoldl f g z t = appEndo (getDual (bifoldMap (Dual . Endo . flip f) (Dual . Endo . flip g) t)) z + {-# INLINE bifoldl #-} + +#if __GLASGOW_HASKELL__ >= 708 + {-# MINIMAL bifoldr | bifoldMap #-} +#endif + +#if __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 710 +deriving instance Typeable Bifoldable +#endif + +instance Bifoldable Arg where + bifoldMap f g (Arg a b) = f a `mappend` g b + +instance Bifoldable (,) where + bifoldMap f g ~(a, b) = f a `mappend` g b + {-# INLINE bifoldMap #-} + +instance Bifoldable Const where + bifoldMap f _ (Const a) = f a + {-# INLINE bifoldMap #-} + +instance Bifoldable Constant where + bifoldMap f _ (Constant a) = f a + {-# INLINE bifoldMap #-} + +#if __GLASGOW_HASKELL__ >= 702 +instance Bifoldable (K1 i) where + bifoldMap f _ (K1 c) = f c + {-# INLINE bifoldMap #-} +#endif + +instance Bifoldable ((,,) x) where + bifoldMap f g ~(_,a,b) = f a `mappend` g b + {-# INLINE bifoldMap #-} + +instance Bifoldable ((,,,) x y) where + bifoldMap f g ~(_,_,a,b) = f a `mappend` g b + {-# INLINE bifoldMap #-} + +instance Bifoldable ((,,,,) x y z) where + bifoldMap f g ~(_,_,_,a,b) = f a `mappend` g b + {-# INLINE bifoldMap #-} + +instance Bifoldable ((,,,,,) x y z w) where + bifoldMap f g ~(_,_,_,_,a,b) = f a `mappend` g b + {-# INLINE bifoldMap #-} + +instance Bifoldable ((,,,,,,) x y z w v) where + bifoldMap f g ~(_,_,_,_,_,a,b) = f a `mappend` g b + {-# INLINE bifoldMap #-} + +#ifdef MIN_VERSION_tagged +instance Bifoldable Tagged where + bifoldMap _ g (Tagged b) = g b + {-# INLINE bifoldMap #-} +#endif + +instance Bifoldable Either where + bifoldMap f _ (Left a) = f a + bifoldMap _ g (Right b) = g b + {-# INLINE bifoldMap #-} + +-- | As 'bifoldr', but strict in the result of the reduction functions at each +-- step. +bifoldr' :: Bifoldable t => (a -> c -> c) -> (b -> c -> c) -> c -> t a b -> c +bifoldr' f g z0 xs = bifoldl f' g' id xs z0 where + f' k x z = k $! f x z + g' k x z = k $! g x z +{-# INLINE bifoldr' #-} + +-- | A variant of 'bifoldr' that has no base case, +-- and thus may only be applied to non-empty structures. +bifoldr1 :: Bifoldable t => (a -> a -> a) -> t a a -> a +bifoldr1 f xs = fromMaybe (error "bifoldr1: empty structure") + (bifoldr mbf mbf Nothing xs) + where + mbf x m = Just (case m of + Nothing -> x + Just y -> f x y) +{-# INLINE bifoldr1 #-} + +-- | Right associative monadic bifold over a structure. +bifoldrM :: (Bifoldable t, Monad m) => (a -> c -> m c) -> (b -> c -> m c) -> c -> t a b -> m c +bifoldrM f g z0 xs = bifoldl f' g' return xs z0 where + f' k x z = f x z >>= k + g' k x z = g x z >>= k +{-# INLINE bifoldrM #-} + +-- | As 'bifoldl', but strict in the result of the reduction functions at each +-- step. +-- +-- This ensures that each step of the bifold is forced to weak head normal form +-- before being applied, avoiding the collection of thunks that would otherwise +-- occur. This is often what you want to strictly reduce a finite structure to +-- a single, monolithic result (e.g., 'bilength'). +bifoldl':: Bifoldable t => (a -> b -> a) -> (a -> c -> a) -> a -> t b c -> a +bifoldl' f g z0 xs = bifoldr f' g' id xs z0 where + f' x k z = k $! f z x + g' x k z = k $! g z x +{-# INLINE bifoldl' #-} + +-- | A variant of 'bifoldl' that has no base case, +-- and thus may only be applied to non-empty structures. +bifoldl1 :: Bifoldable t => (a -> a -> a) -> t a a -> a +bifoldl1 f xs = fromMaybe (error "bifoldl1: empty structure") + (bifoldl mbf mbf Nothing xs) + where + mbf m y = Just (case m of + Nothing -> y + Just x -> f x y) +{-# INLINe bifoldl1 #-} + +-- | Left associative monadic bifold over a structure. +bifoldlM :: (Bifoldable t, Monad m) => (a -> b -> m a) -> (a -> c -> m a) -> a -> t b c -> m a +bifoldlM f g z0 xs = bifoldr f' g' return xs z0 where + f' x k z = f z x >>= k + g' x k z = g z x >>= k +{-# INLINE bifoldlM #-} + +-- | Map each element of a structure using one of two actions, evaluate these +-- actions from left to right, and ignore the results. For a version that +-- doesn't ignore the results, see 'Data.Bitraversable.bitraverse'. +bitraverse_ :: (Bifoldable t, Applicative f) => (a -> f c) -> (b -> f d) -> t a b -> f () +bitraverse_ f g = bifoldr ((*>) . f) ((*>) . g) (pure ()) +{-# INLINE bitraverse_ #-} + +-- | As 'bitraverse_', but with the structure as the primary argument. For a +-- version that doesn't ignore the results, see 'Data.Bitraversable.bifor'. +-- +-- >>> > bifor_ ('a', "bc") print (print . reverse) +-- 'a' +-- "cb" +bifor_ :: (Bifoldable t, Applicative f) => t a b -> (a -> f c) -> (b -> f d) -> f () +bifor_ t f g = bitraverse_ f g t +{-# INLINE bifor_ #-} + +-- | As 'Data.Bitraversable.bimapM', but ignores the results of the functions, +-- merely performing the "actions". +bimapM_:: (Bifoldable t, Monad m) => (a -> m c) -> (b -> m d) -> t a b -> m () +bimapM_ f g = bifoldr ((>>) . f) ((>>) . g) (return ()) +{-# INLINE bimapM_ #-} + +-- | As 'bimapM_', but with the structure as the primary argument. +biforM_ :: (Bifoldable t, Monad m) => t a b -> (a -> m c) -> (b -> m d) -> m () +biforM_ t f g = bimapM_ f g t +{-# INLINE biforM_ #-} + +-- | As 'Data.Bitraversable.bisequenceA', but ignores the results of the actions. +bisequenceA_ :: (Bifoldable t, Applicative f) => t (f a) (f b) -> f () +bisequenceA_ = bifoldr (*>) (*>) (pure ()) +{-# INLINE bisequenceA_ #-} + +-- | Evaluate each action in the structure from left to right, and ignore the +-- results. For a version that doesn't ignore the results, see +-- 'Data.Bitraversable.bisequence'. +bisequence_ :: (Bifoldable t, Monad m) => t (m a) (m b) -> m () +bisequence_ = bifoldr (>>) (>>) (return ()) +{-# INLINE bisequence_ #-} + +-- | The sum of a collection of actions, generalizing 'biconcat'. +biasum :: (Bifoldable t, Alternative f) => t (f a) (f a) -> f a +biasum = bifoldr (<|>) (<|>) empty +{-# INLINE biasum #-} + +-- | The sum of a collection of actions, generalizing 'biconcat'. +bimsum :: (Bifoldable t, MonadPlus m) => t (m a) (m a) -> m a +bimsum = bifoldr mplus mplus mzero +{-# INLINE bimsum #-} + +-- | Collects the list of elements of a structure, from left to right. +biList :: Bifoldable t => t a a -> [a] +biList = bifoldr (:) (:) [] +{-# INLINE biList #-} + +-- | Test whether the structure is empty. +binull :: Bifoldable t => t a b -> Bool +binull = bifoldr (\_ _ -> False) (\_ _ -> False) True +{-# INLINE binull #-} + +-- | Returns the size/length of a finite structure as an 'Int'. +bilength :: Bifoldable t => t a b -> Int +bilength = bifoldl' (\c _ -> c+1) (\c _ -> c+1) 0 +{-# INLINE bilength #-} + +-- | Does the element occur in the structure? +bielem :: (Bifoldable t, Eq a) => a -> t a a -> Bool +bielem x = biany (== x) (== x) +{-# INLINE bielem #-} + +-- | Reduces a structure of lists to the concatenation of those lists. +biconcat :: Bifoldable t => t [a] [a] -> [a] +biconcat = bifold +{-# INLINE biconcat #-} + +newtype Max a = Max {getMax :: Maybe a} +newtype Min a = Min {getMin :: Maybe a} + +instance Ord a => Monoid (Max a) where + mempty = Max Nothing + + {-# INLINE mappend #-} + m `mappend` Max Nothing = m + Max Nothing `mappend` n = n + (Max m@(Just x)) `mappend` (Max n@(Just y)) + | x >= y = Max m + | otherwise = Max n + +instance Ord a => Monoid (Min a) where + mempty = Min Nothing + + {-# INLINE mappend #-} + m `mappend` Min Nothing = m + Min Nothing `mappend` n = n + (Min m@(Just x)) `mappend` (Min n@(Just y)) + | x <= y = Min m + | otherwise = Min n + +-- | The largest element of a non-empty structure. +bimaximum :: forall t a. (Bifoldable t, Ord a) => t a a -> a +bimaximum = fromMaybe (error "bimaximum: empty structure") . + getMax . bifoldMap mj mj + where mj = Max #. (Just :: a -> Maybe a) +{-# INLINE bimaximum #-} + +-- | The least element of a non-empty structure. +biminimum :: forall t a. (Bifoldable t, Ord a) => t a a -> a +biminimum = fromMaybe (error "biminimum: empty structure") . + getMin . bifoldMap mj mj + where mj = Min #. (Just :: a -> Maybe a) +{-# INLINE biminimum #-} + +-- | The 'bisum' function computes the sum of the numbers of a structure. +bisum :: (Bifoldable t, Num a) => t a a -> a +bisum = getSum #. bifoldMap Sum Sum +{-# INLINE bisum #-} + +-- | The 'biproduct' function computes the product of the numbers of a +-- structure. +biproduct :: (Bifoldable t, Num a) => t a a -> a +biproduct = getProduct #. bifoldMap Product Product +{-# INLINE biproduct #-} + +-- | Given a means of mapping the elements of a structure to lists, computes the +-- concatenation of all such lists in order. +biconcatMap :: Bifoldable t => (a -> [c]) -> (b -> [c]) -> t a b -> [c] +biconcatMap = bifoldMap +{-# INLINE biconcatMap #-} + +-- | 'biand' returns the conjunction of a container of Bools. For the +-- result to be 'True', the container must be finite; 'False', however, +-- results from a 'False' value finitely far from the left end. +biand :: Bifoldable t => t Bool Bool -> Bool +biand = getAll #. bifoldMap All All +{-# INLINE biand #-} + +-- | 'bior' returns the disjunction of a container of Bools. For the +-- result to be 'False', the container must be finite; 'True', however, +-- results from a 'True' value finitely far from the left end. +bior :: Bifoldable t => t Bool Bool -> Bool +bior = getAny #. bifoldMap Any Any +{-# INLINE bior #-} + +-- | Determines whether any element of the structure satisfies the appropriate +-- predicate. +biany :: Bifoldable t => (a -> Bool) -> (b -> Bool) -> t a b -> Bool +biany p q = getAny #. bifoldMap (Any . p) (Any . q) +{-# INLINE biany #-} + +-- | Determines whether all elements of the structure satisfy the appropriate +-- predicate. +biall :: Bifoldable t => (a -> Bool) -> (b -> Bool) -> t a b -> Bool +biall p q = getAll #. bifoldMap (All . p) (All . q) +{-# INLINE biall #-} + +-- | The largest element of a non-empty structure with respect to the +-- given comparison function. +bimaximumBy :: Bifoldable t => (a -> a -> Ordering) -> t a a -> a +bimaximumBy cmp = bifoldr1 max' + where max' x y = case cmp x y of + GT -> x + _ -> y +{-# INLINE bimaximumBy #-} + +-- | The least element of a non-empty structure with respect to the +-- given comparison function. +biminimumBy :: Bifoldable t => (a -> a -> Ordering) -> t a a -> a +biminimumBy cmp = bifoldr1 min' + where min' x y = case cmp x y of + GT -> y + _ -> x +{-# INLINE biminimumBy #-} + +-- | 'binotElem' is the negation of 'bielem'. +binotElem :: (Bifoldable t, Eq a) => a -> t a a-> Bool +binotElem x = not . bielem x +{-# INLINE binotElem #-} + +-- | The 'bifind' function takes a predicate and a structure and returns +-- the leftmost element of the structure matching the predicate, or +-- 'Nothing' if there is no such element. +bifind :: Bifoldable t => (a -> Bool) -> t a a -> Maybe a +bifind p = getFirst . bifoldMap finder finder + where finder x = First (if p x then Just x else Nothing) +{-# INLINE bifind #-} + +-- See Note [Function coercion] +#if MIN_VERSION_base(4,7,0) +(#.) :: Coercible b c => (b -> c) -> (a -> b) -> (a -> c) +(#.) _f = coerce +#else +(#.) :: (b -> c) -> (a -> b) -> (a -> c) +(#.) _f = unsafeCoerce +#endif +{-# INLINE (#.) #-} + +{- +Note [Function coercion] +~~~~~~~~~~~~~~~~~~~~~~~~ + +Several functions here use (#.) instead of (.) to avoid potential efficiency +problems relating to #7542. The problem, in a nutshell: + +If N is a newtype constructor, then N x will always have the same +representation as x (something similar applies for a newtype deconstructor). +However, if f is a function, + +N . f = \x -> N (f x) + +This looks almost the same as f, but the eta expansion lifts it--the lhs could +be _|_, but the rhs never is. This can lead to very inefficient code. Thus we +steal a technique from Shachaf and Edward Kmett and adapt it to the current +(rather clean) setting. Instead of using N . f, we use N .## f, which is +just + +coerce f `asTypeOf` (N . f) + +That is, we just *pretend* that f has the right type, and thanks to the safety +of coerce, the type checker guarantees that nothing really goes wrong. We still +have to be a bit careful, though: remember that #. completely ignores the +*value* of its left operand. +-} diff --git a/old-src/ghc801/Data/Bitraversable.hs b/old-src/ghc801/Data/Bitraversable.hs --- a/old-src/ghc801/Data/Bitraversable.hs +++ b/old-src/ghc801/Data/Bitraversable.hs @@ -1,320 +1,320 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE ScopedTypeVariables #-} -{-# LANGUAGE StandaloneDeriving #-} - -#if __GLASGOW_HASKELL__ >= 704 -{-# LANGUAGE Trustworthy #-} -#endif - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2011-2015 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bitraversable - ( Bitraversable(..) - , bisequenceA - , bisequence - , bimapM - , bifor - , biforM - , bimapAccumL - , bimapAccumR - , bimapDefault - , bifoldMapDefault - ) where - -import Control.Applicative -import Control.Monad.Trans.Instances () -import Data.Bifunctor -import Data.Bifoldable -import Data.Functor.Constant -import Data.Functor.Identity -import Data.Orphans () - -#if MIN_VERSION_base(4,7,0) -import Data.Coerce (coerce) -#else -import Unsafe.Coerce (unsafeCoerce) -#endif - -#if !(MIN_VERSION_base(4,8,0)) -import Data.Monoid -#endif - -import Data.Semigroup (Arg(..)) - -#ifdef MIN_VERSION_tagged -import Data.Tagged -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics (K1(..)) -#endif - -#if __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 710 -import Data.Typeable -#endif - --- | 'Bitraversable' identifies bifunctorial data structures whose elements can --- be traversed in order, performing 'Applicative' or 'Monad' actions at each --- element, and collecting a result structure with the same shape. --- --- As opposed to 'Traversable' data structures, which have one variety of --- element on which an action can be performed, 'Bitraversable' data structures --- have two such varieties of elements. --- --- A definition of 'bitraverse' must satisfy the following laws: --- --- [/naturality/] --- @'bitraverse' (t . f) (t . g) ≡ t . 'bitraverse' f g@ --- for every applicative transformation @t@ --- --- [/identity/] --- @'bitraverse' 'Identity' 'Identity' ≡ 'Identity'@ --- --- [/composition/] --- @'Compose' . 'fmap' ('bitraverse' g1 g2) . 'bitraverse' f1 f2 --- ≡ 'bitraverse' ('Compose' . 'fmap' g1 . f1) ('Compose' . 'fmap' g2 . f2)@ --- --- where an /applicative transformation/ is a function --- --- @t :: ('Applicative' f, 'Applicative' g) => f a -> g a@ --- --- preserving the 'Applicative' operations: --- --- @ --- t ('pure' x) = 'pure' x --- t (f '<*>' x) = t f '<*>' t x --- @ --- --- and the identity functor 'Identity' and composition functors 'Compose' are --- defined as --- --- > newtype Identity a = Identity { runIdentity :: a } --- > --- > instance Functor Identity where --- > fmap f (Identity x) = Identity (f x) --- > --- > instance Applicative Identity where --- > pure = Identity --- > Identity f <*> Identity x = Identity (f x) --- > --- > newtype Compose f g a = Compose (f (g a)) --- > --- > instance (Functor f, Functor g) => Functor (Compose f g) where --- > fmap f (Compose x) = Compose (fmap (fmap f) x) --- > --- > instance (Applicative f, Applicative g) => Applicative (Compose f g) where --- > pure = Compose . pure . pure --- > Compose f <*> Compose x = Compose ((<*>) <$> f <*> x) --- --- Some simple examples are 'Either' and '(,)': --- --- > instance Bitraversable Either where --- > bitraverse f _ (Left x) = Left <$> f x --- > bitraverse _ g (Right y) = Right <$> g y --- > --- > instance Bitraversable (,) where --- > bitraverse f g (x, y) = (,) <$> f x <*> g y --- --- 'Bitraversable' relates to its superclasses in the following ways: --- --- @ --- 'bimap' f g ≡ 'runIdentity' . 'bitraverse' ('Identity' . f) ('Identity' . g) --- 'bifoldMap' f g = 'getConst' . 'bitraverse' ('Const' . f) ('Const' . g) --- @ --- --- These are available as 'bimapDefault' and 'bifoldMapDefault' respectively. -class (Bifunctor t, Bifoldable t) => Bitraversable t where - -- | Evaluates the relevant functions at each element in the structure, running - -- the action, and builds a new structure with the same shape, using the - -- elements produced from sequencing the actions. - -- - -- @'bitraverse' f g ≡ 'bisequenceA' . 'bimap' f g@ - -- - -- For a version that ignores the results, see 'bitraverse_'. - bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> t a b -> f (t c d) - - --- | Sequences all the actions in a structure, building a new structure with the --- same shape using the results of the actions. For a version that ignores the --- results, see 'bisequenceA_'. --- --- @'bisequenceA' ≡ 'bitraverse' 'id' 'id'@ -bisequenceA :: (Bitraversable t, Applicative f) => t (f a) (f b) -> f (t a b) -bisequenceA = bitraverse id id -{-# INLINE bisequenceA #-} - --- | As 'bitraverse', but uses evidence that @m@ is a 'Monad' rather than an --- 'Applicative'. For a version that ignores the results, see 'bimapM_'. --- --- @ --- 'bimapM' f g ≡ 'bisequence' . 'bimap' f g --- 'bimapM' f g ≡ 'unwrapMonad' . 'bitraverse' ('WrapMonad' . f) ('WrapMonad' . g) --- @ -bimapM :: (Bitraversable t, Monad m) => (a -> m c) -> (b -> m d) -> t a b -> m (t c d) -bimapM f g = unwrapMonad . bitraverse (WrapMonad . f) (WrapMonad . g) -{-# INLINE bimapM #-} - --- | As 'bisequenceA', but uses evidence that @m@ is a 'Monad' rather than an --- 'Applicative'. For a version that ignores the results, see 'bisequence_'. --- --- @ --- 'bisequence' ≡ 'bimapM' 'id' 'id' --- 'bisequence' ≡ 'unwrapMonad' . 'bisequenceA' . 'bimap' 'WrapMonad' 'WrapMonad' --- @ -bisequence :: (Bitraversable t, Monad m) => t (m a) (m b) -> m (t a b) -bisequence = bimapM id id -{-# INLINE bisequence #-} - -#if __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 710 -deriving instance Typeable Bitraversable -#endif - -instance Bitraversable Arg where - bitraverse f g (Arg a b) = Arg <$> f a <*> g b - -instance Bitraversable (,) where - bitraverse f g ~(a, b) = (,) <$> f a <*> g b - {-# INLINE bitraverse #-} - -instance Bitraversable ((,,) x) where - bitraverse f g ~(x, a, b) = (,,) x <$> f a <*> g b - {-# INLINE bitraverse #-} - -instance Bitraversable ((,,,) x y) where - bitraverse f g ~(x, y, a, b) = (,,,) x y <$> f a <*> g b - {-# INLINE bitraverse #-} - -instance Bitraversable ((,,,,) x y z) where - bitraverse f g ~(x, y, z, a, b) = (,,,,) x y z <$> f a <*> g b - {-# INLINE bitraverse #-} - -instance Bitraversable ((,,,,,) x y z w) where - bitraverse f g ~(x, y, z, w, a, b) = (,,,,,) x y z w <$> f a <*> g b - {-# INLINE bitraverse #-} - -instance Bitraversable ((,,,,,,) x y z w v) where - bitraverse f g ~(x, y, z, w, v, a, b) = (,,,,,,) x y z w v <$> f a <*> g b - {-# INLINE bitraverse #-} - -instance Bitraversable Either where - bitraverse f _ (Left a) = Left <$> f a - bitraverse _ g (Right b) = Right <$> g b - {-# INLINE bitraverse #-} - -instance Bitraversable Const where - bitraverse f _ (Const a) = Const <$> f a - {-# INLINE bitraverse #-} - -instance Bitraversable Constant where - bitraverse f _ (Constant a) = Constant <$> f a - {-# INLINE bitraverse #-} - -#if __GLASGOW_HASKELL__ >= 702 -instance Bitraversable (K1 i) where - bitraverse f _ (K1 c) = K1 <$> f c - {-# INLINE bitraverse #-} -#endif - -#ifdef MIN_VERSION_tagged -instance Bitraversable Tagged where - bitraverse _ g (Tagged b) = Tagged <$> g b - {-# INLINE bitraverse #-} -#endif - --- | 'bifor' is 'bitraverse' with the structure as the first argument. For a --- version that ignores the results, see 'bifor_'. -bifor :: (Bitraversable t, Applicative f) => t a b -> (a -> f c) -> (b -> f d) -> f (t c d) -bifor t f g = bitraverse f g t -{-# INLINE bifor #-} - --- | 'biforM' is 'bimapM' with the structure as the first argument. For a --- version that ignores the results, see 'biforM_'. -biforM :: (Bitraversable t, Monad m) => t a b -> (a -> m c) -> (b -> m d) -> m (t c d) -biforM t f g = bimapM f g t -{-# INLINE biforM #-} - --- | left-to-right state transformer -newtype StateL s a = StateL { runStateL :: s -> (s, a) } - -instance Functor (StateL s) where - fmap f (StateL k) = StateL $ \ s -> - let (s', v) = k s in (s', f v) - {-# INLINE fmap #-} - -instance Applicative (StateL s) where - pure x = StateL (\ s -> (s, x)) - {-# INLINE pure #-} - StateL kf <*> StateL kv = StateL $ \ s -> - let (s', f) = kf s - (s'', v) = kv s' - in (s'', f v) - {-# INLINE (<*>) #-} - --- | The 'bimapAccumL' function behaves like a combination of 'bimap' and --- 'bifoldl'; it traverses a structure from left to right, threading a state --- of type @a@ and using the given actions to compute new elements for the --- structure. -bimapAccumL :: Bitraversable t => (a -> b -> (a, c)) -> (a -> d -> (a, e)) -> a -> t b d -> (a, t c e) -bimapAccumL f g s t = runStateL (bitraverse (StateL . flip f) (StateL . flip g) t) s -{-# INLINE bimapAccumL #-} - --- | right-to-left state transformer -newtype StateR s a = StateR { runStateR :: s -> (s, a) } - -instance Functor (StateR s) where - fmap f (StateR k) = StateR $ \ s -> - let (s', v) = k s in (s', f v) - {-# INLINE fmap #-} - -instance Applicative (StateR s) where - pure x = StateR (\ s -> (s, x)) - {-# INLINE pure #-} - StateR kf <*> StateR kv = StateR $ \ s -> - let (s', v) = kv s - (s'', f) = kf s' - in (s'', f v) - {-# INLINE (<*>) #-} - --- | The 'bimapAccumR' function behaves like a combination of 'bimap' and --- 'bifoldl'; it traverses a structure from right to left, threading a state --- of type @a@ and using the given actions to compute new elements for the --- structure. -bimapAccumR :: Bitraversable t => (a -> b -> (a, c)) -> (a -> d -> (a, e)) -> a -> t b d -> (a, t c e) -bimapAccumR f g s t = runStateR (bitraverse (StateR . flip f) (StateR . flip g) t) s -{-# INLINE bimapAccumR #-} - --- | A default definition of 'bimap' in terms of the 'Bitraversable' operations. --- --- @'bimapDefault' f g ≡ --- 'runIdentity' . 'bitraverse' ('Identity' . f) ('Identity' . g)@ -bimapDefault :: forall t a b c d . Bitraversable t - => (a -> b) -> (c -> d) -> t a c -> t b d -bimapDefault = coerce - (bitraverse :: (a -> Identity b) - -> (c -> Identity d) -> t a c -> Identity (t b d)) -{-# INLINE bimapDefault #-} - --- | A default definition of 'bifoldMap' in terms of the 'Bitraversable' operations. --- --- @'bifoldMapDefault' f g ≡ --- 'getConst' . 'bitraverse' ('Const' . f) ('Const' . g)@ -bifoldMapDefault :: forall t m a b . (Bitraversable t, Monoid m) - => (a -> m) -> (b -> m) -> t a b -> m -bifoldMapDefault = coerce - (bitraverse :: (a -> Const m ()) - -> (b -> Const m ()) -> t a b -> Const m (t () ())) -{-# INLINE bifoldMapDefault #-} - -#if !(MIN_VERSION_base(4,7,0)) -coerce :: a -> b -coerce = unsafeCoerce -#endif +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# LANGUAGE StandaloneDeriving #-} + +#if __GLASGOW_HASKELL__ >= 704 +{-# LANGUAGE Trustworthy #-} +#endif + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2011-2015 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +---------------------------------------------------------------------------- +module Data.Bitraversable + ( Bitraversable(..) + , bisequenceA + , bisequence + , bimapM + , bifor + , biforM + , bimapAccumL + , bimapAccumR + , bimapDefault + , bifoldMapDefault + ) where + +import Control.Applicative +import Control.Monad.Trans.Instances () +import Data.Bifunctor +import Data.Bifoldable +import Data.Functor.Constant +import Data.Functor.Identity +import Data.Orphans () + +#if MIN_VERSION_base(4,7,0) +import Data.Coerce (coerce) +#else +import Unsafe.Coerce (unsafeCoerce) +#endif + +#if !(MIN_VERSION_base(4,8,0)) +import Data.Monoid +#endif + +import Data.Semigroup (Arg(..)) + +#ifdef MIN_VERSION_tagged +import Data.Tagged +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics (K1(..)) +#endif + +#if __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 710 +import Data.Typeable +#endif + +-- | 'Bitraversable' identifies bifunctorial data structures whose elements can +-- be traversed in order, performing 'Applicative' or 'Monad' actions at each +-- element, and collecting a result structure with the same shape. +-- +-- As opposed to 'Traversable' data structures, which have one variety of +-- element on which an action can be performed, 'Bitraversable' data structures +-- have two such varieties of elements. +-- +-- A definition of 'bitraverse' must satisfy the following laws: +-- +-- [/naturality/] +-- @'bitraverse' (t . f) (t . g) ≡ t . 'bitraverse' f g@ +-- for every applicative transformation @t@ +-- +-- [/identity/] +-- @'bitraverse' 'Identity' 'Identity' ≡ 'Identity'@ +-- +-- [/composition/] +-- @'Compose' . 'fmap' ('bitraverse' g1 g2) . 'bitraverse' f1 f2 +-- ≡ 'bitraverse' ('Compose' . 'fmap' g1 . f1) ('Compose' . 'fmap' g2 . f2)@ +-- +-- where an /applicative transformation/ is a function +-- +-- @t :: ('Applicative' f, 'Applicative' g) => f a -> g a@ +-- +-- preserving the 'Applicative' operations: +-- +-- @ +-- t ('pure' x) = 'pure' x +-- t (f '<*>' x) = t f '<*>' t x +-- @ +-- +-- and the identity functor 'Identity' and composition functors 'Compose' are +-- defined as +-- +-- > newtype Identity a = Identity { runIdentity :: a } +-- > +-- > instance Functor Identity where +-- > fmap f (Identity x) = Identity (f x) +-- > +-- > instance Applicative Identity where +-- > pure = Identity +-- > Identity f <*> Identity x = Identity (f x) +-- > +-- > newtype Compose f g a = Compose (f (g a)) +-- > +-- > instance (Functor f, Functor g) => Functor (Compose f g) where +-- > fmap f (Compose x) = Compose (fmap (fmap f) x) +-- > +-- > instance (Applicative f, Applicative g) => Applicative (Compose f g) where +-- > pure = Compose . pure . pure +-- > Compose f <*> Compose x = Compose ((<*>) <$> f <*> x) +-- +-- Some simple examples are 'Either' and '(,)': +-- +-- > instance Bitraversable Either where +-- > bitraverse f _ (Left x) = Left <$> f x +-- > bitraverse _ g (Right y) = Right <$> g y +-- > +-- > instance Bitraversable (,) where +-- > bitraverse f g (x, y) = (,) <$> f x <*> g y +-- +-- 'Bitraversable' relates to its superclasses in the following ways: +-- +-- @ +-- 'bimap' f g ≡ 'runIdentity' . 'bitraverse' ('Identity' . f) ('Identity' . g) +-- 'bifoldMap' f g = 'getConst' . 'bitraverse' ('Const' . f) ('Const' . g) +-- @ +-- +-- These are available as 'bimapDefault' and 'bifoldMapDefault' respectively. +class (Bifunctor t, Bifoldable t) => Bitraversable t where + -- | Evaluates the relevant functions at each element in the structure, running + -- the action, and builds a new structure with the same shape, using the + -- elements produced from sequencing the actions. + -- + -- @'bitraverse' f g ≡ 'bisequenceA' . 'bimap' f g@ + -- + -- For a version that ignores the results, see 'bitraverse_'. + bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> t a b -> f (t c d) + + +-- | Sequences all the actions in a structure, building a new structure with the +-- same shape using the results of the actions. For a version that ignores the +-- results, see 'bisequenceA_'. +-- +-- @'bisequenceA' ≡ 'bitraverse' 'id' 'id'@ +bisequenceA :: (Bitraversable t, Applicative f) => t (f a) (f b) -> f (t a b) +bisequenceA = bitraverse id id +{-# INLINE bisequenceA #-} + +-- | As 'bitraverse', but uses evidence that @m@ is a 'Monad' rather than an +-- 'Applicative'. For a version that ignores the results, see 'bimapM_'. +-- +-- @ +-- 'bimapM' f g ≡ 'bisequence' . 'bimap' f g +-- 'bimapM' f g ≡ 'unwrapMonad' . 'bitraverse' ('WrapMonad' . f) ('WrapMonad' . g) +-- @ +bimapM :: (Bitraversable t, Monad m) => (a -> m c) -> (b -> m d) -> t a b -> m (t c d) +bimapM f g = unwrapMonad . bitraverse (WrapMonad . f) (WrapMonad . g) +{-# INLINE bimapM #-} + +-- | As 'bisequenceA', but uses evidence that @m@ is a 'Monad' rather than an +-- 'Applicative'. For a version that ignores the results, see 'bisequence_'. +-- +-- @ +-- 'bisequence' ≡ 'bimapM' 'id' 'id' +-- 'bisequence' ≡ 'unwrapMonad' . 'bisequenceA' . 'bimap' 'WrapMonad' 'WrapMonad' +-- @ +bisequence :: (Bitraversable t, Monad m) => t (m a) (m b) -> m (t a b) +bisequence = bimapM id id +{-# INLINE bisequence #-} + +#if __GLASGOW_HASKELL__ >= 708 && __GLASGOW_HASKELL__ < 710 +deriving instance Typeable Bitraversable +#endif + +instance Bitraversable Arg where + bitraverse f g (Arg a b) = Arg <$> f a <*> g b + +instance Bitraversable (,) where + bitraverse f g ~(a, b) = (,) <$> f a <*> g b + {-# INLINE bitraverse #-} + +instance Bitraversable ((,,) x) where + bitraverse f g ~(x, a, b) = (,,) x <$> f a <*> g b + {-# INLINE bitraverse #-} + +instance Bitraversable ((,,,) x y) where + bitraverse f g ~(x, y, a, b) = (,,,) x y <$> f a <*> g b + {-# INLINE bitraverse #-} + +instance Bitraversable ((,,,,) x y z) where + bitraverse f g ~(x, y, z, a, b) = (,,,,) x y z <$> f a <*> g b + {-# INLINE bitraverse #-} + +instance Bitraversable ((,,,,,) x y z w) where + bitraverse f g ~(x, y, z, w, a, b) = (,,,,,) x y z w <$> f a <*> g b + {-# INLINE bitraverse #-} + +instance Bitraversable ((,,,,,,) x y z w v) where + bitraverse f g ~(x, y, z, w, v, a, b) = (,,,,,,) x y z w v <$> f a <*> g b + {-# INLINE bitraverse #-} + +instance Bitraversable Either where + bitraverse f _ (Left a) = Left <$> f a + bitraverse _ g (Right b) = Right <$> g b + {-# INLINE bitraverse #-} + +instance Bitraversable Const where + bitraverse f _ (Const a) = Const <$> f a + {-# INLINE bitraverse #-} + +instance Bitraversable Constant where + bitraverse f _ (Constant a) = Constant <$> f a + {-# INLINE bitraverse #-} + +#if __GLASGOW_HASKELL__ >= 702 +instance Bitraversable (K1 i) where + bitraverse f _ (K1 c) = K1 <$> f c + {-# INLINE bitraverse #-} +#endif + +#ifdef MIN_VERSION_tagged +instance Bitraversable Tagged where + bitraverse _ g (Tagged b) = Tagged <$> g b + {-# INLINE bitraverse #-} +#endif + +-- | 'bifor' is 'bitraverse' with the structure as the first argument. For a +-- version that ignores the results, see 'bifor_'. +bifor :: (Bitraversable t, Applicative f) => t a b -> (a -> f c) -> (b -> f d) -> f (t c d) +bifor t f g = bitraverse f g t +{-# INLINE bifor #-} + +-- | 'biforM' is 'bimapM' with the structure as the first argument. For a +-- version that ignores the results, see 'biforM_'. +biforM :: (Bitraversable t, Monad m) => t a b -> (a -> m c) -> (b -> m d) -> m (t c d) +biforM t f g = bimapM f g t +{-# INLINE biforM #-} + +-- | left-to-right state transformer +newtype StateL s a = StateL { runStateL :: s -> (s, a) } + +instance Functor (StateL s) where + fmap f (StateL k) = StateL $ \ s -> + let (s', v) = k s in (s', f v) + {-# INLINE fmap #-} + +instance Applicative (StateL s) where + pure x = StateL (\ s -> (s, x)) + {-# INLINE pure #-} + StateL kf <*> StateL kv = StateL $ \ s -> + let (s', f) = kf s + (s'', v) = kv s' + in (s'', f v) + {-# INLINE (<*>) #-} + +-- | The 'bimapAccumL' function behaves like a combination of 'bimap' and +-- 'bifoldl'; it traverses a structure from left to right, threading a state +-- of type @a@ and using the given actions to compute new elements for the +-- structure. +bimapAccumL :: Bitraversable t => (a -> b -> (a, c)) -> (a -> d -> (a, e)) -> a -> t b d -> (a, t c e) +bimapAccumL f g s t = runStateL (bitraverse (StateL . flip f) (StateL . flip g) t) s +{-# INLINE bimapAccumL #-} + +-- | right-to-left state transformer +newtype StateR s a = StateR { runStateR :: s -> (s, a) } + +instance Functor (StateR s) where + fmap f (StateR k) = StateR $ \ s -> + let (s', v) = k s in (s', f v) + {-# INLINE fmap #-} + +instance Applicative (StateR s) where + pure x = StateR (\ s -> (s, x)) + {-# INLINE pure #-} + StateR kf <*> StateR kv = StateR $ \ s -> + let (s', v) = kv s + (s'', f) = kf s' + in (s'', f v) + {-# INLINE (<*>) #-} + +-- | The 'bimapAccumR' function behaves like a combination of 'bimap' and +-- 'bifoldl'; it traverses a structure from right to left, threading a state +-- of type @a@ and using the given actions to compute new elements for the +-- structure. +bimapAccumR :: Bitraversable t => (a -> b -> (a, c)) -> (a -> d -> (a, e)) -> a -> t b d -> (a, t c e) +bimapAccumR f g s t = runStateR (bitraverse (StateR . flip f) (StateR . flip g) t) s +{-# INLINE bimapAccumR #-} + +-- | A default definition of 'bimap' in terms of the 'Bitraversable' operations. +-- +-- @'bimapDefault' f g ≡ +-- 'runIdentity' . 'bitraverse' ('Identity' . f) ('Identity' . g)@ +bimapDefault :: forall t a b c d . Bitraversable t + => (a -> b) -> (c -> d) -> t a c -> t b d +bimapDefault = coerce + (bitraverse :: (a -> Identity b) + -> (c -> Identity d) -> t a c -> Identity (t b d)) +{-# INLINE bimapDefault #-} + +-- | A default definition of 'bifoldMap' in terms of the 'Bitraversable' operations. +-- +-- @'bifoldMapDefault' f g ≡ +-- 'getConst' . 'bitraverse' ('Const' . f) ('Const' . g)@ +bifoldMapDefault :: forall t m a b . (Bitraversable t, Monoid m) + => (a -> m) -> (b -> m) -> t a b -> m +bifoldMapDefault = coerce + (bitraverse :: (a -> Const m ()) + -> (b -> Const m ()) -> t a b -> Const m (t () ())) +{-# INLINE bifoldMapDefault #-} + +#if !(MIN_VERSION_base(4,7,0)) +coerce :: a -> b +coerce = unsafeCoerce +#endif diff --git a/src/Data/Biapplicative.hs b/src/Data/Biapplicative.hs --- a/src/Data/Biapplicative.hs +++ b/src/Data/Biapplicative.hs @@ -1,327 +1,327 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE GADTs #-} -{-# LANGUAGE RankNTypes #-} -{-# LANGUAGE ScopedTypeVariables #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2011-2015 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Biapplicative ( - -- * Biapplicative bifunctors - Biapplicative(..) - , (<<$>>) - , (<<**>>) - , biliftA3 - , traverseBia - , sequenceBia - , traverseBiaWith - , module Data.Bifunctor - ) where - -import Control.Applicative -import Data.Bifunctor -import Data.Functor.Identity -import GHC.Exts (inline) - -#if !(MIN_VERSION_base(4,8,0)) -import Data.Monoid -import Data.Traversable (Traversable (traverse)) -#endif - -import Data.Semigroup (Arg(..)) - -#ifdef MIN_VERSION_tagged -import Data.Tagged -#endif - -infixl 4 <<$>>, <<*>>, <<*, *>>, <<**>> -(<<$>>) :: (a -> b) -> a -> b -(<<$>>) = id -{-# INLINE (<<$>>) #-} - -class Bifunctor p => Biapplicative p where -#if __GLASGOW_HASKELL__ >= 708 - {-# MINIMAL bipure, ((<<*>>) | biliftA2 ) #-} -#endif - bipure :: a -> b -> p a b - - (<<*>>) :: p (a -> b) (c -> d) -> p a c -> p b d - (<<*>>) = biliftA2 id id - {-# INLINE (<<*>>) #-} - - -- | Lift binary functions - biliftA2 :: (a -> b -> c) -> (d -> e -> f) -> p a d -> p b e -> p c f - biliftA2 f g a b = bimap f g <<$>> a <<*>> b - {-# INLINE biliftA2 #-} - - -- | - -- @ - -- a '*>>' b ≡ 'bimap' ('const' 'id') ('const' 'id') '<<$>>' a '<<*>>' b - -- @ - (*>>) :: p a b -> p c d -> p c d - a *>> b = biliftA2 (const id) (const id) a b - {-# INLINE (*>>) #-} - - -- | - -- @ - -- a '<<*' b ≡ 'bimap' 'const' 'const' '<<$>>' a '<<*>>' b - -- @ - (<<*) :: p a b -> p c d -> p a b - a <<* b = biliftA2 const const a b - {-# INLINE (<<*) #-} - -(<<**>>) :: Biapplicative p => p a c -> p (a -> b) (c -> d) -> p b d -(<<**>>) = biliftA2 (flip id) (flip id) -{-# INLINE (<<**>>) #-} - - --- | Lift ternary functions -biliftA3 :: Biapplicative w => (a -> b -> c -> d) -> (e -> f -> g -> h) -> w a e -> w b f -> w c g -> w d h -biliftA3 f g a b c = biliftA2 f g a b <<*>> c -{-# INLINE biliftA3 #-} - --- | Traverse a 'Traversable' container in a 'Biapplicative'. --- --- 'traverseBia' satisfies the following properties: --- --- [/Pairing/] --- --- @'traverseBia' (,) t = (t, t)@ --- --- [/Composition/] --- --- @'traverseBia' ('Data.Bifunctor.Biff.Biff' . 'bimap' g h . f) = 'Data.Bifunctor.Biff.Biff' . 'bimap' ('traverse' g) ('traverse' h) . 'traverseBia' f@ --- --- @'traverseBia' ('Data.Bifunctor.Tannen.Tannen' . 'fmap' f . g) = 'Data.Bifunctor.Tannen.Tannen' . 'fmap' ('traverseBia' f) . 'traverse' g@ --- --- [/Naturality/] --- --- @ t . 'traverseBia' f = 'traverseBia' (t . f) @ --- --- for every biapplicative transformation @t@. --- --- A /biapplicative transformation/ from a 'Biapplicative' @P@ to a 'Biapplicative' @Q@ --- is a function --- --- @t :: P a b -> Q a b@ --- --- preserving the 'Biapplicative' operations. That is, --- --- * @t ('bipure' x y) = 'bipure' x y@ --- --- * @t (x '<<*>>' y) = t x '<<*>>' t y@ --- --- === Performance note --- --- 'traverseBia' is fairly efficient, and uses compiler rewrite rules --- to be even more efficient for a few important types like @[]@. However, --- if performance is critical, you might consider writing a container-specific --- implementation. -traverseBia :: (Traversable t, Biapplicative p) - => (a -> p b c) -> t a -> p (t b) (t c) -traverseBia = inline (traverseBiaWith traverse) --- We explicitly inline traverseBiaWith because it seems likely to help --- specialization. I'm not much of an expert at the inlining business, --- so I won't mind if someone else decides to do this differently. - --- We use a staged INLINABLE so we can rewrite traverseBia to specialized --- versions for a few important types. -{-# INLINABLE [1] traverseBia #-} - --- | Perform all the 'Biappicative' actions in a 'Traversable' container --- and produce a container with all the results. --- --- @ --- sequenceBia = 'traverseBia' id --- @ -sequenceBia :: (Traversable t, Biapplicative p) - => t (p b c) -> p (t b) (t c) -sequenceBia = inline (traverseBia id) -{-# INLINABLE sequenceBia #-} - --- | A version of 'traverseBia' that doesn't care how the traversal is --- done. --- --- @ --- 'traverseBia' = traverseBiaWith traverse --- @ -traverseBiaWith :: forall p a b c s t. Biapplicative p - => (forall f x. Applicative f => (a -> f x) -> s -> f (t x)) - -> (a -> p b c) -> s -> p (t b) (t c) -traverseBiaWith trav p s = smash p (trav One s) -{-# INLINABLE traverseBiaWith #-} - -smash :: forall p t a b c. Biapplicative p - => (a -> p b c) - -> (forall x. Mag a x (t x)) - -> p (t b) (t c) -smash p m = go m m - where - go :: forall x y. Mag a b x -> Mag a c y -> p x y - go (Pure t) (Pure u) = bipure t u - go (Map f x) (Map g y) = bimap f g (go x y) - go (Ap fs xs) (Ap gs ys) = go fs gs <<*>> go xs ys -#if MIN_VERSION_base(4,10,0) - go (LiftA2 f xs ys) (LiftA2 g zs ws) = biliftA2 f g (go xs zs) (go ys ws) -#endif - go (One x) (One _) = p x - go _ _ = impossibleError -{-# INLINABLE smash #-} - --- Let's not end up with a bunch of CallStack junk in the smash --- unfolding. -impossibleError :: a -impossibleError = error "Impossible: the arguments are always the same." - --- This is used to reify a traversal for 'traverseBia'. It's a somewhat --- bogus 'Functor' and 'Applicative' closely related to 'Magma' from the --- @lens@ package. Valid traversals don't use (<$), (<*), or (*>), so --- we leave them out. We offer all the rest of the Functor and Applicative --- operations to improve performance: we generally want to keep the structure --- as small as possible. We might even consider using RULES to widen lifts --- when we can: --- --- liftA2 f x y <*> z ==> liftA3 f x y z, --- --- etc., up to the pointer tagging limit. But we do need to be careful. I don't --- *think* GHC will ever inline the traversal into the go function (because that --- would duplicate work), but if it did, and if different RULES fired for the --- two copies, everything would break horribly. --- --- Note: if it's necessary for some reason, we *could* relax GADTs to --- ExistentialQuantification by changing the type of One to --- --- One :: (b -> c) -> a -> Mag a b c --- --- where the function will always end up being id. But we allocate a *lot* --- of One constructors, so this would definitely be bad for performance. -data Mag a b t where - Pure :: t -> Mag a b t - Map :: (x -> t) -> Mag a b x -> Mag a b t - Ap :: Mag a b (t -> u) -> Mag a b t -> Mag a b u -#if MIN_VERSION_base(4,10,0) - LiftA2 :: (t -> u -> v) -> Mag a b t -> Mag a b u -> Mag a b v -#endif - One :: a -> Mag a b b - -instance Functor (Mag a b) where - fmap = Map - -instance Applicative (Mag a b) where - pure = Pure - (<*>) = Ap -#if MIN_VERSION_base(4,10,0) - liftA2 = LiftA2 -#endif - --- Rewrite rules for traversing a few important types. These avoid the overhead --- of allocating and matching on a Mag. -{-# RULES -"traverseBia/list" forall f t. traverseBia f t = traverseBiaList f t -"traverseBia/Maybe" forall f t. traverseBia f t = traverseBiaMaybe f t -"traverseBia/Either" forall f t. traverseBia f t = traverseBiaEither f t -"traverseBia/Identity" forall f t. traverseBia f t = traverseBiaIdentity f t -"traverseBia/Const" forall f t. traverseBia f t = traverseBiaConst f t -"traverseBia/Pair" forall f t. traverseBia f t = traverseBiaPair f t - #-} - -traverseBiaList :: Biapplicative p => (a -> p b c) -> [a] -> p [b] [c] -traverseBiaList f = foldr go (bipure [] []) - where - go x r = biliftA2 (:) (:) (f x) r - -traverseBiaMaybe :: Biapplicative p => (a -> p b c) -> Maybe a -> p (Maybe b) (Maybe c) -traverseBiaMaybe _f Nothing = bipure Nothing Nothing -traverseBiaMaybe f (Just x) = bimap Just Just (f x) - -traverseBiaEither :: Biapplicative p => (a -> p b c) -> Either e a -> p (Either e b) (Either e c) -traverseBiaEither f (Right x) = bimap Right Right (f x) -traverseBiaEither _f (Left (e :: e)) = bipure m m - where - m :: Either e x - m = Left e - -traverseBiaIdentity :: Biapplicative p => (a -> p b c) -> Identity a -> p (Identity b) (Identity c) -traverseBiaIdentity f (Identity x) = bimap Identity Identity (f x) - -traverseBiaConst :: Biapplicative p => (a -> p b c) -> Const x a -> p (Const x b) (Const x c) -traverseBiaConst _f (Const x) = bipure (Const x) (Const x) - -traverseBiaPair :: Biapplicative p => (a -> p b c) -> (e, a) -> p (e, b) (e, c) -traverseBiaPair f (x,y) = bimap ((,) x) ((,) x) (f y) - ----------------------------------------------- --- --- Instances - -instance Biapplicative (,) where - bipure = (,) - {-# INLINE bipure #-} - ~(f, g) <<*>> ~(a, b) = (f a, g b) - {-# INLINE (<<*>>) #-} - biliftA2 f g ~(x, y) ~(a, b) = (f x a, g y b) - {-# INLINE biliftA2 #-} - -instance Biapplicative Arg where - bipure = Arg - {-# INLINE bipure #-} - Arg f g <<*>> Arg a b = Arg (f a) (g b) - {-# INLINE (<<*>>) #-} - biliftA2 f g (Arg x y) (Arg a b) = Arg (f x a) (g y b) - {-# INLINE biliftA2 #-} - -instance Monoid x => Biapplicative ((,,) x) where - bipure = (,,) mempty - {-# INLINE bipure #-} - ~(x, f, g) <<*>> ~(x', a, b) = (mappend x x', f a, g b) - {-# INLINE (<<*>>) #-} - -instance (Monoid x, Monoid y) => Biapplicative ((,,,) x y) where - bipure = (,,,) mempty mempty - {-# INLINE bipure #-} - ~(x, y, f, g) <<*>> ~(x', y', a, b) = (mappend x x', mappend y y', f a, g b) - {-# INLINE (<<*>>) #-} - -instance (Monoid x, Monoid y, Monoid z) => Biapplicative ((,,,,) x y z) where - bipure = (,,,,) mempty mempty mempty - {-# INLINE bipure #-} - ~(x, y, z, f, g) <<*>> ~(x', y', z', a, b) = (mappend x x', mappend y y', mappend z z', f a, g b) - {-# INLINE (<<*>>) #-} - -instance (Monoid x, Monoid y, Monoid z, Monoid w) => Biapplicative ((,,,,,) x y z w) where - bipure = (,,,,,) mempty mempty mempty mempty - {-# INLINE bipure #-} - ~(x, y, z, w, f, g) <<*>> ~(x', y', z', w', a, b) = (mappend x x', mappend y y', mappend z z', mappend w w', f a, g b) - {-# INLINE (<<*>>) #-} - -instance (Monoid x, Monoid y, Monoid z, Monoid w, Monoid v) => Biapplicative ((,,,,,,) x y z w v) where - bipure = (,,,,,,) mempty mempty mempty mempty mempty - {-# INLINE bipure #-} - ~(x, y, z, w, v, f, g) <<*>> ~(x', y', z', w', v', a, b) = (mappend x x', mappend y y', mappend z z', mappend w w', mappend v v', f a, g b) - {-# INLINE (<<*>>) #-} - -#ifdef MIN_VERSION_tagged -instance Biapplicative Tagged where - bipure _ b = Tagged b - {-# INLINE bipure #-} - - Tagged f <<*>> Tagged x = Tagged (f x) - {-# INLINE (<<*>>) #-} -#endif - -instance Biapplicative Const where - bipure a _ = Const a - {-# INLINE bipure #-} - Const f <<*>> Const x = Const (f x) - {-# INLINE (<<*>>) #-} +{-# LANGUAGE CPP #-} +{-# LANGUAGE GADTs #-} +{-# LANGUAGE RankNTypes #-} +{-# LANGUAGE ScopedTypeVariables #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2011-2015 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +---------------------------------------------------------------------------- +module Data.Biapplicative ( + -- * Biapplicative bifunctors + Biapplicative(..) + , (<<$>>) + , (<<**>>) + , biliftA3 + , traverseBia + , sequenceBia + , traverseBiaWith + , module Data.Bifunctor + ) where + +import Control.Applicative +import Data.Bifunctor +import Data.Functor.Identity +import GHC.Exts (inline) + +#if !(MIN_VERSION_base(4,8,0)) +import Data.Monoid +import Data.Traversable (Traversable (traverse)) +#endif + +import Data.Semigroup (Arg(..)) + +#ifdef MIN_VERSION_tagged +import Data.Tagged +#endif + +infixl 4 <<$>>, <<*>>, <<*, *>>, <<**>> +(<<$>>) :: (a -> b) -> a -> b +(<<$>>) = id +{-# INLINE (<<$>>) #-} + +class Bifunctor p => Biapplicative p where +#if __GLASGOW_HASKELL__ >= 708 + {-# MINIMAL bipure, ((<<*>>) | biliftA2 ) #-} +#endif + bipure :: a -> b -> p a b + + (<<*>>) :: p (a -> b) (c -> d) -> p a c -> p b d + (<<*>>) = biliftA2 id id + {-# INLINE (<<*>>) #-} + + -- | Lift binary functions + biliftA2 :: (a -> b -> c) -> (d -> e -> f) -> p a d -> p b e -> p c f + biliftA2 f g a b = bimap f g <<$>> a <<*>> b + {-# INLINE biliftA2 #-} + + -- | + -- @ + -- a '*>>' b ≡ 'bimap' ('const' 'id') ('const' 'id') '<<$>>' a '<<*>>' b + -- @ + (*>>) :: p a b -> p c d -> p c d + a *>> b = biliftA2 (const id) (const id) a b + {-# INLINE (*>>) #-} + + -- | + -- @ + -- a '<<*' b ≡ 'bimap' 'const' 'const' '<<$>>' a '<<*>>' b + -- @ + (<<*) :: p a b -> p c d -> p a b + a <<* b = biliftA2 const const a b + {-# INLINE (<<*) #-} + +(<<**>>) :: Biapplicative p => p a c -> p (a -> b) (c -> d) -> p b d +(<<**>>) = biliftA2 (flip id) (flip id) +{-# INLINE (<<**>>) #-} + + +-- | Lift ternary functions +biliftA3 :: Biapplicative w => (a -> b -> c -> d) -> (e -> f -> g -> h) -> w a e -> w b f -> w c g -> w d h +biliftA3 f g a b c = biliftA2 f g a b <<*>> c +{-# INLINE biliftA3 #-} + +-- | Traverse a 'Traversable' container in a 'Biapplicative'. +-- +-- 'traverseBia' satisfies the following properties: +-- +-- [/Pairing/] +-- +-- @'traverseBia' (,) t = (t, t)@ +-- +-- [/Composition/] +-- +-- @'traverseBia' ('Data.Bifunctor.Biff.Biff' . 'bimap' g h . f) = 'Data.Bifunctor.Biff.Biff' . 'bimap' ('traverse' g) ('traverse' h) . 'traverseBia' f@ +-- +-- @'traverseBia' ('Data.Bifunctor.Tannen.Tannen' . 'fmap' f . g) = 'Data.Bifunctor.Tannen.Tannen' . 'fmap' ('traverseBia' f) . 'traverse' g@ +-- +-- [/Naturality/] +-- +-- @ t . 'traverseBia' f = 'traverseBia' (t . f) @ +-- +-- for every biapplicative transformation @t@. +-- +-- A /biapplicative transformation/ from a 'Biapplicative' @P@ to a 'Biapplicative' @Q@ +-- is a function +-- +-- @t :: P a b -> Q a b@ +-- +-- preserving the 'Biapplicative' operations. That is, +-- +-- * @t ('bipure' x y) = 'bipure' x y@ +-- +-- * @t (x '<<*>>' y) = t x '<<*>>' t y@ +-- +-- === Performance note +-- +-- 'traverseBia' is fairly efficient, and uses compiler rewrite rules +-- to be even more efficient for a few important types like @[]@. However, +-- if performance is critical, you might consider writing a container-specific +-- implementation. +traverseBia :: (Traversable t, Biapplicative p) + => (a -> p b c) -> t a -> p (t b) (t c) +traverseBia = inline (traverseBiaWith traverse) +-- We explicitly inline traverseBiaWith because it seems likely to help +-- specialization. I'm not much of an expert at the inlining business, +-- so I won't mind if someone else decides to do this differently. + +-- We use a staged INLINABLE so we can rewrite traverseBia to specialized +-- versions for a few important types. +{-# INLINABLE [1] traverseBia #-} + +-- | Perform all the 'Biappicative' actions in a 'Traversable' container +-- and produce a container with all the results. +-- +-- @ +-- sequenceBia = 'traverseBia' id +-- @ +sequenceBia :: (Traversable t, Biapplicative p) + => t (p b c) -> p (t b) (t c) +sequenceBia = inline (traverseBia id) +{-# INLINABLE sequenceBia #-} + +-- | A version of 'traverseBia' that doesn't care how the traversal is +-- done. +-- +-- @ +-- 'traverseBia' = traverseBiaWith traverse +-- @ +traverseBiaWith :: forall p a b c s t. Biapplicative p + => (forall f x. Applicative f => (a -> f x) -> s -> f (t x)) + -> (a -> p b c) -> s -> p (t b) (t c) +traverseBiaWith trav p s = smash p (trav One s) +{-# INLINABLE traverseBiaWith #-} + +smash :: forall p t a b c. Biapplicative p + => (a -> p b c) + -> (forall x. Mag a x (t x)) + -> p (t b) (t c) +smash p m = go m m + where + go :: forall x y. Mag a b x -> Mag a c y -> p x y + go (Pure t) (Pure u) = bipure t u + go (Map f x) (Map g y) = bimap f g (go x y) + go (Ap fs xs) (Ap gs ys) = go fs gs <<*>> go xs ys +#if MIN_VERSION_base(4,10,0) + go (LiftA2 f xs ys) (LiftA2 g zs ws) = biliftA2 f g (go xs zs) (go ys ws) +#endif + go (One x) (One _) = p x + go _ _ = impossibleError +{-# INLINABLE smash #-} + +-- Let's not end up with a bunch of CallStack junk in the smash +-- unfolding. +impossibleError :: a +impossibleError = error "Impossible: the arguments are always the same." + +-- This is used to reify a traversal for 'traverseBia'. It's a somewhat +-- bogus 'Functor' and 'Applicative' closely related to 'Magma' from the +-- @lens@ package. Valid traversals don't use (<$), (<*), or (*>), so +-- we leave them out. We offer all the rest of the Functor and Applicative +-- operations to improve performance: we generally want to keep the structure +-- as small as possible. We might even consider using RULES to widen lifts +-- when we can: +-- +-- liftA2 f x y <*> z ==> liftA3 f x y z, +-- +-- etc., up to the pointer tagging limit. But we do need to be careful. I don't +-- *think* GHC will ever inline the traversal into the go function (because that +-- would duplicate work), but if it did, and if different RULES fired for the +-- two copies, everything would break horribly. +-- +-- Note: if it's necessary for some reason, we *could* relax GADTs to +-- ExistentialQuantification by changing the type of One to +-- +-- One :: (b -> c) -> a -> Mag a b c +-- +-- where the function will always end up being id. But we allocate a *lot* +-- of One constructors, so this would definitely be bad for performance. +data Mag a b t where + Pure :: t -> Mag a b t + Map :: (x -> t) -> Mag a b x -> Mag a b t + Ap :: Mag a b (t -> u) -> Mag a b t -> Mag a b u +#if MIN_VERSION_base(4,10,0) + LiftA2 :: (t -> u -> v) -> Mag a b t -> Mag a b u -> Mag a b v +#endif + One :: a -> Mag a b b + +instance Functor (Mag a b) where + fmap = Map + +instance Applicative (Mag a b) where + pure = Pure + (<*>) = Ap +#if MIN_VERSION_base(4,10,0) + liftA2 = LiftA2 +#endif + +-- Rewrite rules for traversing a few important types. These avoid the overhead +-- of allocating and matching on a Mag. +{-# RULES +"traverseBia/list" forall f t. traverseBia f t = traverseBiaList f t +"traverseBia/Maybe" forall f t. traverseBia f t = traverseBiaMaybe f t +"traverseBia/Either" forall f t. traverseBia f t = traverseBiaEither f t +"traverseBia/Identity" forall f t. traverseBia f t = traverseBiaIdentity f t +"traverseBia/Const" forall f t. traverseBia f t = traverseBiaConst f t +"traverseBia/Pair" forall f t. traverseBia f t = traverseBiaPair f t + #-} + +traverseBiaList :: Biapplicative p => (a -> p b c) -> [a] -> p [b] [c] +traverseBiaList f = foldr go (bipure [] []) + where + go x r = biliftA2 (:) (:) (f x) r + +traverseBiaMaybe :: Biapplicative p => (a -> p b c) -> Maybe a -> p (Maybe b) (Maybe c) +traverseBiaMaybe _f Nothing = bipure Nothing Nothing +traverseBiaMaybe f (Just x) = bimap Just Just (f x) + +traverseBiaEither :: Biapplicative p => (a -> p b c) -> Either e a -> p (Either e b) (Either e c) +traverseBiaEither f (Right x) = bimap Right Right (f x) +traverseBiaEither _f (Left (e :: e)) = bipure m m + where + m :: Either e x + m = Left e + +traverseBiaIdentity :: Biapplicative p => (a -> p b c) -> Identity a -> p (Identity b) (Identity c) +traverseBiaIdentity f (Identity x) = bimap Identity Identity (f x) + +traverseBiaConst :: Biapplicative p => (a -> p b c) -> Const x a -> p (Const x b) (Const x c) +traverseBiaConst _f (Const x) = bipure (Const x) (Const x) + +traverseBiaPair :: Biapplicative p => (a -> p b c) -> (e, a) -> p (e, b) (e, c) +traverseBiaPair f (x,y) = bimap ((,) x) ((,) x) (f y) + +---------------------------------------------- +-- +-- Instances + +instance Biapplicative (,) where + bipure = (,) + {-# INLINE bipure #-} + ~(f, g) <<*>> ~(a, b) = (f a, g b) + {-# INLINE (<<*>>) #-} + biliftA2 f g ~(x, y) ~(a, b) = (f x a, g y b) + {-# INLINE biliftA2 #-} + +instance Biapplicative Arg where + bipure = Arg + {-# INLINE bipure #-} + Arg f g <<*>> Arg a b = Arg (f a) (g b) + {-# INLINE (<<*>>) #-} + biliftA2 f g (Arg x y) (Arg a b) = Arg (f x a) (g y b) + {-# INLINE biliftA2 #-} + +instance Monoid x => Biapplicative ((,,) x) where + bipure = (,,) mempty + {-# INLINE bipure #-} + ~(x, f, g) <<*>> ~(x', a, b) = (mappend x x', f a, g b) + {-# INLINE (<<*>>) #-} + +instance (Monoid x, Monoid y) => Biapplicative ((,,,) x y) where + bipure = (,,,) mempty mempty + {-# INLINE bipure #-} + ~(x, y, f, g) <<*>> ~(x', y', a, b) = (mappend x x', mappend y y', f a, g b) + {-# INLINE (<<*>>) #-} + +instance (Monoid x, Monoid y, Monoid z) => Biapplicative ((,,,,) x y z) where + bipure = (,,,,) mempty mempty mempty + {-# INLINE bipure #-} + ~(x, y, z, f, g) <<*>> ~(x', y', z', a, b) = (mappend x x', mappend y y', mappend z z', f a, g b) + {-# INLINE (<<*>>) #-} + +instance (Monoid x, Monoid y, Monoid z, Monoid w) => Biapplicative ((,,,,,) x y z w) where + bipure = (,,,,,) mempty mempty mempty mempty + {-# INLINE bipure #-} + ~(x, y, z, w, f, g) <<*>> ~(x', y', z', w', a, b) = (mappend x x', mappend y y', mappend z z', mappend w w', f a, g b) + {-# INLINE (<<*>>) #-} + +instance (Monoid x, Monoid y, Monoid z, Monoid w, Monoid v) => Biapplicative ((,,,,,,) x y z w v) where + bipure = (,,,,,,) mempty mempty mempty mempty mempty + {-# INLINE bipure #-} + ~(x, y, z, w, v, f, g) <<*>> ~(x', y', z', w', v', a, b) = (mappend x x', mappend y y', mappend z z', mappend w w', mappend v v', f a, g b) + {-# INLINE (<<*>>) #-} + +#ifdef MIN_VERSION_tagged +instance Biapplicative Tagged where + bipure _ b = Tagged b + {-# INLINE bipure #-} + + Tagged f <<*>> Tagged x = Tagged (f x) + {-# INLINE (<<*>>) #-} +#endif + +instance Biapplicative Const where + bipure a _ = Const a + {-# INLINE bipure #-} + Const f <<*>> Const x = Const (f x) + {-# INLINE (<<*>>) #-} diff --git a/src/Data/Bifunctor/Biap.hs b/src/Data/Bifunctor/Biap.hs --- a/src/Data/Bifunctor/Biap.hs +++ b/src/Data/Bifunctor/Biap.hs @@ -1,169 +1,169 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE EmptyDataDecls #-} -{-# LANGUAGE FlexibleContexts #-} -{-# LANGUAGE DeriveTraversable #-} -{-# LANGUAGE GeneralizedNewtypeDeriving #-} -{-# LANGUAGE ScopedTypeVariables #-} -{-# LANGUAGE TypeFamilies #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - --- This module uses GND -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif -#include "bifunctors-common.h" - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2008-2016 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bifunctor.Biap - ( Biap(..) - ) where - -import Control.Applicative -import Control.Monad -import qualified Control.Monad.Fail as Fail (MonadFail) -import Data.Biapplicative -import Data.Bifoldable -import Data.Bitraversable -import Data.Functor.Classes - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif - -#if !(MIN_VERSION_base(4,8,0)) -import Data.Foldable -import Data.Monoid -import Data.Traversable -#endif - -import qualified Data.Semigroup as S - --- | Pointwise lifting of a class over two arguments, using --- 'Biapplicative'. --- --- Classes that can be lifted include 'Monoid', 'Num' and --- 'Bounded'. Each method of those classes can be defined as lifting --- themselves over each argument of 'Biapplicative'. --- --- @ --- mempty = bipure mempty mempty --- minBound = bipure minBound minBound --- maxBound = bipure maxBound maxBound --- fromInteger n = bipure (fromInteger n) (fromInteger n) --- --- negate = bimap negate negate --- --- (+) = biliftA2 (+) (+) --- (<>) = biliftA2 (<>) (<>) --- @ --- --- 'Biap' is to 'Biapplicative' as 'Data.Monoid.Ap' is to --- 'Applicative'. --- --- 'Biap' can be used with @DerivingVia@ to derive a numeric instance --- for pairs: --- --- @ --- newtype Numpair a = Np (a, a) --- deriving (S.Semigroup, Monoid, Num, Bounded) --- via Biap (,) a a --- @ --- -newtype Biap bi a b = Biap { getBiap :: bi a b } - deriving ( Eq - , Ord - , Show - , Read - , Enum - , Functor - , Foldable - , Traversable - , Alternative - , Applicative -#if __GLASGOW_HASKELL__ >= 702 - , Generic -#endif -#if __GLASGOW_HASKELL__ >= 706 - , Generic1 -#endif - , Monad - , Fail.MonadFail - , MonadPlus - , Eq1 - , Ord1 - - , Bifunctor - , Biapplicative - , Bifoldable -#if LIFTED_FUNCTOR_CLASSES - , Eq2 - , Ord2 -#endif - ) - -instance Bitraversable bi => Bitraversable (Biap bi) where - bitraverse f g (Biap as) = Biap <$> bitraverse f g as - -instance (Biapplicative bi, S.Semigroup a, S.Semigroup b) => S.Semigroup (Biap bi a b) where - (<>) = biliftA2 (S.<>) (S.<>) - -instance (Biapplicative bi, Monoid a, Monoid b) => Monoid (Biap bi a b) where - mempty = bipure mempty mempty -#if !(MIN_VERSION_base(4,11,0)) - mappend = biliftA2 mappend mappend -#endif - -instance (Biapplicative bi, Bounded a, Bounded b) => Bounded (Biap bi a b) where - minBound = bipure minBound minBound - maxBound = bipure maxBound maxBound - -instance ( Biapplicative bi, Num a, Num b -#if !(MIN_VERSION_base(4,5,0)) - -- Old versions of Num have Eq and Show as superclasses. Sigh. - , Eq (bi a b), Show (bi a b) -#endif - ) => Num (Biap bi a b) where - (+) = biliftA2 (+) (+) - (*) = biliftA2 (*) (*) - - negate = bimap negate negate - abs = bimap abs abs - signum = bimap signum signum - - fromInteger n = bipure (fromInteger n) (fromInteger n) - -#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 706 -data BiapMetaData -data BiapMetaCons -data BiapMetaSel - -instance Datatype BiapMetaData where - datatypeName = const "Biap" - moduleName = const "Data.Bifunctor.Wrapped" - -instance Constructor BiapMetaCons where - conName = const "Biap" - conIsRecord = const True - -instance Selector BiapMetaSel where - selName = const "getBiap" - -instance Generic1 (Biap p a) where - type Rep1 (Biap p a) = D1 BiapMetaData - (C1 BiapMetaCons - (S1 BiapMetaSel (Rec1 (p a)))) - from1 = M1 . M1 . M1 . Rec1 . getBiap - to1 = Biap . unRec1 . unM1 . unM1 . unM1 -#endif +{-# LANGUAGE CPP #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE DeriveTraversable #-} +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# LANGUAGE TypeFamilies #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +-- This module uses GND +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif +#include "bifunctors-common.h" + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2008-2016 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +---------------------------------------------------------------------------- +module Data.Bifunctor.Biap + ( Biap(..) + ) where + +import Control.Applicative +import Control.Monad +import qualified Control.Monad.Fail as Fail (MonadFail) +import Data.Biapplicative +import Data.Bifoldable +import Data.Bitraversable +import Data.Functor.Classes + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif + +#if !(MIN_VERSION_base(4,8,0)) +import Data.Foldable +import Data.Monoid +import Data.Traversable +#endif + +import qualified Data.Semigroup as S + +-- | Pointwise lifting of a class over two arguments, using +-- 'Biapplicative'. +-- +-- Classes that can be lifted include 'Monoid', 'Num' and +-- 'Bounded'. Each method of those classes can be defined as lifting +-- themselves over each argument of 'Biapplicative'. +-- +-- @ +-- mempty = bipure mempty mempty +-- minBound = bipure minBound minBound +-- maxBound = bipure maxBound maxBound +-- fromInteger n = bipure (fromInteger n) (fromInteger n) +-- +-- negate = bimap negate negate +-- +-- (+) = biliftA2 (+) (+) +-- (<>) = biliftA2 (<>) (<>) +-- @ +-- +-- 'Biap' is to 'Biapplicative' as 'Data.Monoid.Ap' is to +-- 'Applicative'. +-- +-- 'Biap' can be used with @DerivingVia@ to derive a numeric instance +-- for pairs: +-- +-- @ +-- newtype Numpair a = Np (a, a) +-- deriving (S.Semigroup, Monoid, Num, Bounded) +-- via Biap (,) a a +-- @ +-- +newtype Biap bi a b = Biap { getBiap :: bi a b } + deriving ( Eq + , Ord + , Show + , Read + , Enum + , Functor + , Foldable + , Traversable + , Alternative + , Applicative +#if __GLASGOW_HASKELL__ >= 702 + , Generic +#endif +#if __GLASGOW_HASKELL__ >= 706 + , Generic1 +#endif + , Monad + , Fail.MonadFail + , MonadPlus + , Eq1 + , Ord1 + + , Bifunctor + , Biapplicative + , Bifoldable +#if LIFTED_FUNCTOR_CLASSES + , Eq2 + , Ord2 +#endif + ) + +instance Bitraversable bi => Bitraversable (Biap bi) where + bitraverse f g (Biap as) = Biap <$> bitraverse f g as + +instance (Biapplicative bi, S.Semigroup a, S.Semigroup b) => S.Semigroup (Biap bi a b) where + (<>) = biliftA2 (S.<>) (S.<>) + +instance (Biapplicative bi, Monoid a, Monoid b) => Monoid (Biap bi a b) where + mempty = bipure mempty mempty +#if !(MIN_VERSION_base(4,11,0)) + mappend = biliftA2 mappend mappend +#endif + +instance (Biapplicative bi, Bounded a, Bounded b) => Bounded (Biap bi a b) where + minBound = bipure minBound minBound + maxBound = bipure maxBound maxBound + +instance ( Biapplicative bi, Num a, Num b +#if !(MIN_VERSION_base(4,5,0)) + -- Old versions of Num have Eq and Show as superclasses. Sigh. + , Eq (bi a b), Show (bi a b) +#endif + ) => Num (Biap bi a b) where + (+) = biliftA2 (+) (+) + (*) = biliftA2 (*) (*) + + negate = bimap negate negate + abs = bimap abs abs + signum = bimap signum signum + + fromInteger n = bipure (fromInteger n) (fromInteger n) + +#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 706 +data BiapMetaData +data BiapMetaCons +data BiapMetaSel + +instance Datatype BiapMetaData where + datatypeName = const "Biap" + moduleName = const "Data.Bifunctor.Wrapped" + +instance Constructor BiapMetaCons where + conName = const "Biap" + conIsRecord = const True + +instance Selector BiapMetaSel where + selName = const "getBiap" + +instance Generic1 (Biap p a) where + type Rep1 (Biap p a) = D1 BiapMetaData + (C1 BiapMetaCons + (S1 BiapMetaSel (Rec1 (p a)))) + from1 = M1 . M1 . M1 . Rec1 . getBiap + to1 = Biap . unRec1 . unM1 . unM1 . unM1 +#endif diff --git a/src/Data/Bifunctor/Biff.hs b/src/Data/Bifunctor/Biff.hs --- a/src/Data/Bifunctor/Biff.hs +++ b/src/Data/Bifunctor/Biff.hs @@ -1,167 +1,167 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE EmptyDataDecls #-} -{-# LANGUAGE FlexibleContexts #-} -{-# LANGUAGE StandaloneDeriving #-} -{-# LANGUAGE TypeFamilies #-} -{-# LANGUAGE TypeOperators #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif - -#if __GLASGOW_HASKELL__ >= 708 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif -#include "bifunctors-common.h" - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2008-2016 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bifunctor.Biff - ( Biff(..) - ) where - -#if __GLASGOW_HASKELL__ < 710 -import Control.Applicative -#endif - -import Data.Biapplicative -import Data.Bifoldable -import Data.Bitraversable - -#if __GLASGOW_HASKELL__ < 710 -import Data.Foldable -import Data.Monoid -import Data.Traversable -#endif - -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif - -#if LIFTED_FUNCTOR_CLASSES -import Data.Functor.Classes -#endif - --- | Compose two 'Functor's on the inside of a 'Bifunctor'. -newtype Biff p f g a b = Biff { runBiff :: p (f a) (g b) } - deriving ( Eq, Ord, Show, Read -#if __GLASGOW_HASKELL__ >= 702 - , Generic -#endif -#if __GLASGOW_HASKELL__ >= 708 - , Typeable -#endif - ) -#if __GLASGOW_HASKELL__ >= 702 -# if __GLASGOW_HASKELL__ >= 708 -deriving instance Functor (p (f a)) => Generic1 (Biff p f g a) -# else -data BiffMetaData -data BiffMetaCons -data BiffMetaSel - -instance Datatype BiffMetaData where - datatypeName = const "Biff" - moduleName = const "Data.Bifunctor.Biff" - -instance Constructor BiffMetaCons where - conName = const "Biff" - conIsRecord = const True - -instance Selector BiffMetaSel where - selName = const "runBiff" - -instance Functor (p (f a)) => Generic1 (Biff p f g a) where - type Rep1 (Biff p f g a) = D1 BiffMetaData (C1 BiffMetaCons - (S1 BiffMetaSel (p (f a) :.: Rec1 g))) - from1 = M1 . M1 . M1 . Comp1 . fmap Rec1 . runBiff - to1 = Biff . fmap unRec1 . unComp1 . unM1 . unM1 . unM1 -# endif -#endif - -#if LIFTED_FUNCTOR_CLASSES -instance (Eq2 p, Eq1 f, Eq1 g, Eq a) => Eq1 (Biff p f g a) where - liftEq = liftEq2 (==) -instance (Eq2 p, Eq1 f, Eq1 g) => Eq2 (Biff p f g) where - liftEq2 f g (Biff x) (Biff y) = liftEq2 (liftEq f) (liftEq g) x y - -instance (Ord2 p, Ord1 f, Ord1 g, Ord a) => Ord1 (Biff p f g a) where - liftCompare = liftCompare2 compare -instance (Ord2 p, Ord1 f, Ord1 g) => Ord2 (Biff p f g) where - liftCompare2 f g (Biff x) (Biff y) = liftCompare2 (liftCompare f) (liftCompare g) x y - -instance (Read2 p, Read1 f, Read1 g, Read a) => Read1 (Biff p f g a) where - liftReadsPrec = liftReadsPrec2 readsPrec readList -instance (Read2 p, Read1 f, Read1 g) => Read2 (Biff p f g) where - liftReadsPrec2 rp1 rl1 rp2 rl2 p = readParen (p > 10) $ \s0 -> do - ("Biff", s1) <- lex s0 - ("{", s2) <- lex s1 - ("runBiff", s3) <- lex s2 - (x, s4) <- liftReadsPrec2 (liftReadsPrec rp1 rl1) (liftReadList rp1 rl1) - (liftReadsPrec rp2 rl2) (liftReadList rp2 rl2) 0 s3 - ("}", s5) <- lex s4 - return (Biff x, s5) - -instance (Show2 p, Show1 f, Show1 g, Show a) => Show1 (Biff p f g a) where - liftShowsPrec = liftShowsPrec2 showsPrec showList -instance (Show2 p, Show1 f, Show1 g) => Show2 (Biff p f g) where - liftShowsPrec2 sp1 sl1 sp2 sl2 p (Biff x) = showParen (p > 10) $ - showString "Biff {runBiff = " - . liftShowsPrec2 (liftShowsPrec sp1 sl1) (liftShowList sp1 sl1) - (liftShowsPrec sp2 sl2) (liftShowList sp2 sl2) 0 x - . showChar '}' -#endif - -instance (Bifunctor p, Functor f, Functor g) => Bifunctor (Biff p f g) where - first f = Biff . first (fmap f) . runBiff - {-# INLINE first #-} - second f = Biff . second (fmap f) . runBiff - {-# INLINE second #-} - bimap f g = Biff . bimap (fmap f) (fmap g) . runBiff - {-# INLINE bimap #-} - -instance (Bifunctor p, Functor g) => Functor (Biff p f g a) where - fmap f = Biff . second (fmap f) . runBiff - {-# INLINE fmap #-} - -instance (Biapplicative p, Applicative f, Applicative g) => Biapplicative (Biff p f g) where - bipure a b = Biff (bipure (pure a) (pure b)) - {-# INLINE bipure #-} - - Biff fg <<*>> Biff xy = Biff (bimap (<*>) (<*>) fg <<*>> xy) - {-# INLINE (<<*>>) #-} - -instance (Bifoldable p, Foldable g) => Foldable (Biff p f g a) where - foldMap f = bifoldMap (const mempty) (foldMap f) . runBiff - {-# INLINE foldMap #-} - -instance (Bifoldable p, Foldable f, Foldable g) => Bifoldable (Biff p f g) where - bifoldMap f g = bifoldMap (foldMap f) (foldMap g) . runBiff - {-# INLINE bifoldMap #-} - -instance (Bitraversable p, Traversable g) => Traversable (Biff p f g a) where - traverse f = fmap Biff . bitraverse pure (traverse f) . runBiff - {-# INLINE traverse #-} - -instance (Bitraversable p, Traversable f, Traversable g) => Bitraversable (Biff p f g) where - bitraverse f g = fmap Biff . bitraverse (traverse f) (traverse g) . runBiff - {-# INLINE bitraverse #-} +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE TypeFamilies #-} +{-# LANGUAGE TypeOperators #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif + +#if __GLASGOW_HASKELL__ >= 708 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif +#include "bifunctors-common.h" + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2008-2016 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +---------------------------------------------------------------------------- +module Data.Bifunctor.Biff + ( Biff(..) + ) where + +#if __GLASGOW_HASKELL__ < 710 +import Control.Applicative +#endif + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bitraversable + +#if __GLASGOW_HASKELL__ < 710 +import Data.Foldable +import Data.Monoid +import Data.Traversable +#endif + +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif + +#if LIFTED_FUNCTOR_CLASSES +import Data.Functor.Classes +#endif + +-- | Compose two 'Functor's on the inside of a 'Bifunctor'. +newtype Biff p f g a b = Biff { runBiff :: p (f a) (g b) } + deriving ( Eq, Ord, Show, Read +#if __GLASGOW_HASKELL__ >= 702 + , Generic +#endif +#if __GLASGOW_HASKELL__ >= 708 + , Typeable +#endif + ) +#if __GLASGOW_HASKELL__ >= 702 +# if __GLASGOW_HASKELL__ >= 708 +deriving instance Functor (p (f a)) => Generic1 (Biff p f g a) +# else +data BiffMetaData +data BiffMetaCons +data BiffMetaSel + +instance Datatype BiffMetaData where + datatypeName = const "Biff" + moduleName = const "Data.Bifunctor.Biff" + +instance Constructor BiffMetaCons where + conName = const "Biff" + conIsRecord = const True + +instance Selector BiffMetaSel where + selName = const "runBiff" + +instance Functor (p (f a)) => Generic1 (Biff p f g a) where + type Rep1 (Biff p f g a) = D1 BiffMetaData (C1 BiffMetaCons + (S1 BiffMetaSel (p (f a) :.: Rec1 g))) + from1 = M1 . M1 . M1 . Comp1 . fmap Rec1 . runBiff + to1 = Biff . fmap unRec1 . unComp1 . unM1 . unM1 . unM1 +# endif +#endif + +#if LIFTED_FUNCTOR_CLASSES +instance (Eq2 p, Eq1 f, Eq1 g, Eq a) => Eq1 (Biff p f g a) where + liftEq = liftEq2 (==) +instance (Eq2 p, Eq1 f, Eq1 g) => Eq2 (Biff p f g) where + liftEq2 f g (Biff x) (Biff y) = liftEq2 (liftEq f) (liftEq g) x y + +instance (Ord2 p, Ord1 f, Ord1 g, Ord a) => Ord1 (Biff p f g a) where + liftCompare = liftCompare2 compare +instance (Ord2 p, Ord1 f, Ord1 g) => Ord2 (Biff p f g) where + liftCompare2 f g (Biff x) (Biff y) = liftCompare2 (liftCompare f) (liftCompare g) x y + +instance (Read2 p, Read1 f, Read1 g, Read a) => Read1 (Biff p f g a) where + liftReadsPrec = liftReadsPrec2 readsPrec readList +instance (Read2 p, Read1 f, Read1 g) => Read2 (Biff p f g) where + liftReadsPrec2 rp1 rl1 rp2 rl2 p = readParen (p > 10) $ \s0 -> do + ("Biff", s1) <- lex s0 + ("{", s2) <- lex s1 + ("runBiff", s3) <- lex s2 + (x, s4) <- liftReadsPrec2 (liftReadsPrec rp1 rl1) (liftReadList rp1 rl1) + (liftReadsPrec rp2 rl2) (liftReadList rp2 rl2) 0 s3 + ("}", s5) <- lex s4 + return (Biff x, s5) + +instance (Show2 p, Show1 f, Show1 g, Show a) => Show1 (Biff p f g a) where + liftShowsPrec = liftShowsPrec2 showsPrec showList +instance (Show2 p, Show1 f, Show1 g) => Show2 (Biff p f g) where + liftShowsPrec2 sp1 sl1 sp2 sl2 p (Biff x) = showParen (p > 10) $ + showString "Biff {runBiff = " + . liftShowsPrec2 (liftShowsPrec sp1 sl1) (liftShowList sp1 sl1) + (liftShowsPrec sp2 sl2) (liftShowList sp2 sl2) 0 x + . showChar '}' +#endif + +instance (Bifunctor p, Functor f, Functor g) => Bifunctor (Biff p f g) where + first f = Biff . first (fmap f) . runBiff + {-# INLINE first #-} + second f = Biff . second (fmap f) . runBiff + {-# INLINE second #-} + bimap f g = Biff . bimap (fmap f) (fmap g) . runBiff + {-# INLINE bimap #-} + +instance (Bifunctor p, Functor g) => Functor (Biff p f g a) where + fmap f = Biff . second (fmap f) . runBiff + {-# INLINE fmap #-} + +instance (Biapplicative p, Applicative f, Applicative g) => Biapplicative (Biff p f g) where + bipure a b = Biff (bipure (pure a) (pure b)) + {-# INLINE bipure #-} + + Biff fg <<*>> Biff xy = Biff (bimap (<*>) (<*>) fg <<*>> xy) + {-# INLINE (<<*>>) #-} + +instance (Bifoldable p, Foldable g) => Foldable (Biff p f g a) where + foldMap f = bifoldMap (const mempty) (foldMap f) . runBiff + {-# INLINE foldMap #-} + +instance (Bifoldable p, Foldable f, Foldable g) => Bifoldable (Biff p f g) where + bifoldMap f g = bifoldMap (foldMap f) (foldMap g) . runBiff + {-# INLINE bifoldMap #-} + +instance (Bitraversable p, Traversable g) => Traversable (Biff p f g a) where + traverse f = fmap Biff . bitraverse pure (traverse f) . runBiff + {-# INLINE traverse #-} + +instance (Bitraversable p, Traversable f, Traversable g) => Bitraversable (Biff p f g) where + bitraverse f g = fmap Biff . bitraverse (traverse f) (traverse g) . runBiff + {-# INLINE bitraverse #-} diff --git a/src/Data/Bifunctor/Clown.hs b/src/Data/Bifunctor/Clown.hs --- a/src/Data/Bifunctor/Clown.hs +++ b/src/Data/Bifunctor/Clown.hs @@ -1,192 +1,192 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE EmptyDataDecls #-} -{-# LANGUAGE TypeFamilies #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif - -#if __GLASGOW_HASKELL__ >= 708 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif -#include "bifunctors-common.h" - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2008-2016 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- --- From the Functional Pearl \"Clowns to the Left of me, Jokers to the Right: Dissecting Data Structures\" --- by Conor McBride. ----------------------------------------------------------------------------- -module Data.Bifunctor.Clown - ( Clown(..) - ) where - -#if __GLASGOW_HASKELL__ < 710 -import Control.Applicative -#endif - -import Data.Biapplicative -import Data.Bifoldable -import Data.Bitraversable -import Data.Functor.Classes - -#if __GLASGOW_HASKELL__ < 710 -import Data.Foldable -import Data.Monoid -import Data.Traversable -#endif - -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif - --- | Make a 'Functor' over the first argument of a 'Bifunctor'. --- --- Mnemonic: C__l__owns to the __l__eft (parameter of the Bifunctor), --- joke__r__s to the __r__ight. -newtype Clown f a b = Clown { runClown :: f a } - deriving ( Eq, Ord, Show, Read -#if __GLASGOW_HASKELL__ >= 702 - , Generic -#endif -#if __GLASGOW_HASKELL__ >= 708 - , Generic1 - , Typeable -#endif - ) - -#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 708 -data ClownMetaData -data ClownMetaCons -data ClownMetaSel - -instance Datatype ClownMetaData where - datatypeName _ = "Clown" - moduleName _ = "Data.Bifunctor.Clown" - -instance Constructor ClownMetaCons where - conName _ = "Clown" - conIsRecord _ = True - -instance Selector ClownMetaSel where - selName _ = "runClown" - -instance Generic1 (Clown f a) where - type Rep1 (Clown f a) = D1 ClownMetaData (C1 ClownMetaCons - (S1 ClownMetaSel (Rec0 (f a)))) - from1 = M1 . M1 . M1 . K1 . runClown - to1 = Clown . unK1 . unM1 . unM1 . unM1 -#endif - -#if LIFTED_FUNCTOR_CLASSES -instance (Eq1 f, Eq a) => Eq1 (Clown f a) where - liftEq = liftEq2 (==) -instance Eq1 f => Eq2 (Clown f) where - liftEq2 f _ = eqClown (liftEq f) - -instance (Ord1 f, Ord a) => Ord1 (Clown f a) where - liftCompare = liftCompare2 compare -instance Ord1 f => Ord2 (Clown f) where - liftCompare2 f _ = compareClown (liftCompare f) - -instance (Read1 f, Read a) => Read1 (Clown f a) where - liftReadsPrec = liftReadsPrec2 readsPrec readList -instance Read1 f => Read2 (Clown f) where - liftReadsPrec2 rp1 rl1 _ _ = readsPrecClown (liftReadsPrec rp1 rl1) - -instance (Show1 f, Show a) => Show1 (Clown f a) where - liftShowsPrec = liftShowsPrec2 showsPrec showList -instance Show1 f => Show2 (Clown f) where - liftShowsPrec2 sp1 sl1 _ _ = showsPrecClown (liftShowsPrec sp1 sl1) -#else -instance (Eq1 f, Eq a) => Eq1 (Clown f a) where - eq1 = eqClown eq1 - -instance (Ord1 f, Ord a) => Ord1 (Clown f a) where - compare1 = compareClown compare1 - -instance (Read1 f, Read a) => Read1 (Clown f a) where - readsPrec1 = readsPrecClown readsPrec1 - -instance (Show1 f, Show a) => Show1 (Clown f a) where - showsPrec1 = showsPrecClown showsPrec1 -#endif - -eqClown :: (f a1 -> f a2 -> Bool) - -> Clown f a1 b1 -> Clown f a2 b2 -> Bool -eqClown eqA (Clown x) (Clown y) = eqA x y - -compareClown :: (f a1 -> f a2 -> Ordering) - -> Clown f a1 b1 -> Clown f a2 b2 -> Ordering -compareClown compareA (Clown x) (Clown y) = compareA x y - -readsPrecClown :: (Int -> ReadS (f a)) - -> Int -> ReadS (Clown f a b) -readsPrecClown rpA p = - readParen (p > 10) $ \s0 -> do - ("Clown", s1) <- lex s0 - ("{", s2) <- lex s1 - ("runClown", s3) <- lex s2 - (x, s4) <- rpA 0 s3 - ("}", s5) <- lex s4 - return (Clown x, s5) - -showsPrecClown :: (Int -> f a -> ShowS) - -> Int -> Clown f a b -> ShowS -showsPrecClown spA p (Clown x) = - showParen (p > 10) $ - showString "Clown {runClown = " - . spA 0 x - . showChar '}' - -instance Functor f => Bifunctor (Clown f) where - first f = Clown . fmap f . runClown - {-# INLINE first #-} - second _ = Clown . runClown - {-# INLINE second #-} - bimap f _ = Clown . fmap f . runClown - {-# INLINE bimap #-} - -instance Functor (Clown f a) where - fmap _ = Clown . runClown - {-# INLINE fmap #-} - -instance Applicative f => Biapplicative (Clown f) where - bipure a _ = Clown (pure a) - {-# INLINE bipure #-} - - Clown mf <<*>> Clown mx = Clown (mf <*> mx) - {-# INLINE (<<*>>) #-} - -instance Foldable f => Bifoldable (Clown f) where - bifoldMap f _ = foldMap f . runClown - {-# INLINE bifoldMap #-} - -instance Foldable (Clown f a) where - foldMap _ = mempty - {-# INLINE foldMap #-} - -instance Traversable f => Bitraversable (Clown f) where - bitraverse f _ = fmap Clown . traverse f . runClown - {-# INLINE bitraverse #-} - -instance Traversable (Clown f a) where - traverse _ = pure . Clown . runClown - {-# INLINE traverse #-} +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE TypeFamilies #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif + +#if __GLASGOW_HASKELL__ >= 708 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif +#include "bifunctors-common.h" + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2008-2016 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +-- From the Functional Pearl \"Clowns to the Left of me, Jokers to the Right: Dissecting Data Structures\" +-- by Conor McBride. +---------------------------------------------------------------------------- +module Data.Bifunctor.Clown + ( Clown(..) + ) where + +#if __GLASGOW_HASKELL__ < 710 +import Control.Applicative +#endif + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bitraversable +import Data.Functor.Classes + +#if __GLASGOW_HASKELL__ < 710 +import Data.Foldable +import Data.Monoid +import Data.Traversable +#endif + +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif + +-- | Make a 'Functor' over the first argument of a 'Bifunctor'. +-- +-- Mnemonic: C__l__owns to the __l__eft (parameter of the Bifunctor), +-- joke__r__s to the __r__ight. +newtype Clown f a b = Clown { runClown :: f a } + deriving ( Eq, Ord, Show, Read +#if __GLASGOW_HASKELL__ >= 702 + , Generic +#endif +#if __GLASGOW_HASKELL__ >= 708 + , Generic1 + , Typeable +#endif + ) + +#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 708 +data ClownMetaData +data ClownMetaCons +data ClownMetaSel + +instance Datatype ClownMetaData where + datatypeName _ = "Clown" + moduleName _ = "Data.Bifunctor.Clown" + +instance Constructor ClownMetaCons where + conName _ = "Clown" + conIsRecord _ = True + +instance Selector ClownMetaSel where + selName _ = "runClown" + +instance Generic1 (Clown f a) where + type Rep1 (Clown f a) = D1 ClownMetaData (C1 ClownMetaCons + (S1 ClownMetaSel (Rec0 (f a)))) + from1 = M1 . M1 . M1 . K1 . runClown + to1 = Clown . unK1 . unM1 . unM1 . unM1 +#endif + +#if LIFTED_FUNCTOR_CLASSES +instance (Eq1 f, Eq a) => Eq1 (Clown f a) where + liftEq = liftEq2 (==) +instance Eq1 f => Eq2 (Clown f) where + liftEq2 f _ = eqClown (liftEq f) + +instance (Ord1 f, Ord a) => Ord1 (Clown f a) where + liftCompare = liftCompare2 compare +instance Ord1 f => Ord2 (Clown f) where + liftCompare2 f _ = compareClown (liftCompare f) + +instance (Read1 f, Read a) => Read1 (Clown f a) where + liftReadsPrec = liftReadsPrec2 readsPrec readList +instance Read1 f => Read2 (Clown f) where + liftReadsPrec2 rp1 rl1 _ _ = readsPrecClown (liftReadsPrec rp1 rl1) + +instance (Show1 f, Show a) => Show1 (Clown f a) where + liftShowsPrec = liftShowsPrec2 showsPrec showList +instance Show1 f => Show2 (Clown f) where + liftShowsPrec2 sp1 sl1 _ _ = showsPrecClown (liftShowsPrec sp1 sl1) +#else +instance (Eq1 f, Eq a) => Eq1 (Clown f a) where + eq1 = eqClown eq1 + +instance (Ord1 f, Ord a) => Ord1 (Clown f a) where + compare1 = compareClown compare1 + +instance (Read1 f, Read a) => Read1 (Clown f a) where + readsPrec1 = readsPrecClown readsPrec1 + +instance (Show1 f, Show a) => Show1 (Clown f a) where + showsPrec1 = showsPrecClown showsPrec1 +#endif + +eqClown :: (f a1 -> f a2 -> Bool) + -> Clown f a1 b1 -> Clown f a2 b2 -> Bool +eqClown eqA (Clown x) (Clown y) = eqA x y + +compareClown :: (f a1 -> f a2 -> Ordering) + -> Clown f a1 b1 -> Clown f a2 b2 -> Ordering +compareClown compareA (Clown x) (Clown y) = compareA x y + +readsPrecClown :: (Int -> ReadS (f a)) + -> Int -> ReadS (Clown f a b) +readsPrecClown rpA p = + readParen (p > 10) $ \s0 -> do + ("Clown", s1) <- lex s0 + ("{", s2) <- lex s1 + ("runClown", s3) <- lex s2 + (x, s4) <- rpA 0 s3 + ("}", s5) <- lex s4 + return (Clown x, s5) + +showsPrecClown :: (Int -> f a -> ShowS) + -> Int -> Clown f a b -> ShowS +showsPrecClown spA p (Clown x) = + showParen (p > 10) $ + showString "Clown {runClown = " + . spA 0 x + . showChar '}' + +instance Functor f => Bifunctor (Clown f) where + first f = Clown . fmap f . runClown + {-# INLINE first #-} + second _ = Clown . runClown + {-# INLINE second #-} + bimap f _ = Clown . fmap f . runClown + {-# INLINE bimap #-} + +instance Functor (Clown f a) where + fmap _ = Clown . runClown + {-# INLINE fmap #-} + +instance Applicative f => Biapplicative (Clown f) where + bipure a _ = Clown (pure a) + {-# INLINE bipure #-} + + Clown mf <<*>> Clown mx = Clown (mf <*> mx) + {-# INLINE (<<*>>) #-} + +instance Foldable f => Bifoldable (Clown f) where + bifoldMap f _ = foldMap f . runClown + {-# INLINE bifoldMap #-} + +instance Foldable (Clown f a) where + foldMap _ = mempty + {-# INLINE foldMap #-} + +instance Traversable f => Bitraversable (Clown f) where + bitraverse f _ = fmap Clown . traverse f . runClown + {-# INLINE bitraverse #-} + +instance Traversable (Clown f a) where + traverse _ = pure . Clown . runClown + {-# INLINE traverse #-} diff --git a/src/Data/Bifunctor/Fix.hs b/src/Data/Bifunctor/Fix.hs --- a/src/Data/Bifunctor/Fix.hs +++ b/src/Data/Bifunctor/Fix.hs @@ -1,120 +1,120 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE FlexibleContexts #-} -{-# LANGUAGE StandaloneDeriving #-} -{-# LANGUAGE UndecidableInstances #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - -#if __GLASGOW_HASKELL__ >= 704 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif -#include "bifunctors-common.h" - ------------------------------------------------------------------------------ --- | --- Module : Data.Bifunctor.Fix --- Copyright : (C) 2008-2016 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : non-portable --- ------------------------------------------------------------------------------ -module Data.Bifunctor.Fix - ( Fix(..) - ) where - -#if __GLASGOW_HASKELL__ < 710 -import Control.Applicative -#endif - -import Data.Biapplicative -import Data.Bifoldable -import Data.Bitraversable - -#if __GLASGOW_HASKELL__ < 710 -import Data.Foldable -import Data.Traversable -#endif - -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif - -#if LIFTED_FUNCTOR_CLASSES -import Data.Functor.Classes -#endif - --- | Greatest fixpoint of a 'Bifunctor' (a 'Functor' over the first argument with zipping). -newtype Fix p a = In { out :: p (Fix p a) a } - deriving - ( -#if __GLASGOW_HASKELL__ >= 702 - Generic -#endif -#if __GLASGOW_HASKELL__ >= 708 - , Typeable -#endif - ) - -deriving instance Eq (p (Fix p a) a) => Eq (Fix p a) -deriving instance Ord (p (Fix p a) a) => Ord (Fix p a) -deriving instance Show (p (Fix p a) a) => Show (Fix p a) -deriving instance Read (p (Fix p a) a) => Read (Fix p a) - -#if LIFTED_FUNCTOR_CLASSES -instance Eq2 p => Eq1 (Fix p) where - liftEq f (In x) (In y) = liftEq2 (liftEq f) f x y - -instance Ord2 p => Ord1 (Fix p) where - liftCompare f (In x) (In y) = liftCompare2 (liftCompare f) f x y - -instance Read2 p => Read1 (Fix p) where - liftReadsPrec rp1 rl1 p = readParen (p > 10) $ \s0 -> do - ("In", s1) <- lex s0 - ("{", s2) <- lex s1 - ("out", s3) <- lex s2 - (x, s4) <- liftReadsPrec2 (liftReadsPrec rp1 rl1) (liftReadList rp1 rl1) - rp1 rl1 0 s3 - ("}", s5) <- lex s4 - return (In x, s5) - -instance Show2 p => Show1 (Fix p) where - liftShowsPrec sp1 sl1 p (In x) = showParen (p > 10) $ - showString "In {out = " - . liftShowsPrec2 (liftShowsPrec sp1 sl1) (liftShowList sp1 sl1) - sp1 sl1 0 x - . showChar '}' -#endif - -instance Bifunctor p => Functor (Fix p) where - fmap f (In p) = In (bimap (fmap f) f p) - {-# INLINE fmap #-} - -instance Biapplicative p => Applicative (Fix p) where - pure a = In (bipure (pure a) a) - {-# INLINE pure #-} - In p <*> In q = In (biliftA2 (<*>) ($) p q) - {-# INLINE (<*>) #-} - -instance Bifoldable p => Foldable (Fix p) where - foldMap f (In p) = bifoldMap (foldMap f) f p - {-# INLINE foldMap #-} - -instance Bitraversable p => Traversable (Fix p) where - traverse f (In p) = In <$> bitraverse (traverse f) f p - {-# INLINE traverse #-} +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE UndecidableInstances #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +#if __GLASGOW_HASKELL__ >= 704 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif +#include "bifunctors-common.h" + +----------------------------------------------------------------------------- +-- | +-- Module : Data.Bifunctor.Fix +-- Copyright : (C) 2008-2016 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : non-portable +-- +----------------------------------------------------------------------------- +module Data.Bifunctor.Fix + ( Fix(..) + ) where + +#if __GLASGOW_HASKELL__ < 710 +import Control.Applicative +#endif + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bitraversable + +#if __GLASGOW_HASKELL__ < 710 +import Data.Foldable +import Data.Traversable +#endif + +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif + +#if LIFTED_FUNCTOR_CLASSES +import Data.Functor.Classes +#endif + +-- | Greatest fixpoint of a 'Bifunctor' (a 'Functor' over the first argument with zipping). +newtype Fix p a = In { out :: p (Fix p a) a } + deriving + ( +#if __GLASGOW_HASKELL__ >= 702 + Generic +#endif +#if __GLASGOW_HASKELL__ >= 708 + , Typeable +#endif + ) + +deriving instance Eq (p (Fix p a) a) => Eq (Fix p a) +deriving instance Ord (p (Fix p a) a) => Ord (Fix p a) +deriving instance Show (p (Fix p a) a) => Show (Fix p a) +deriving instance Read (p (Fix p a) a) => Read (Fix p a) + +#if LIFTED_FUNCTOR_CLASSES +instance Eq2 p => Eq1 (Fix p) where + liftEq f (In x) (In y) = liftEq2 (liftEq f) f x y + +instance Ord2 p => Ord1 (Fix p) where + liftCompare f (In x) (In y) = liftCompare2 (liftCompare f) f x y + +instance Read2 p => Read1 (Fix p) where + liftReadsPrec rp1 rl1 p = readParen (p > 10) $ \s0 -> do + ("In", s1) <- lex s0 + ("{", s2) <- lex s1 + ("out", s3) <- lex s2 + (x, s4) <- liftReadsPrec2 (liftReadsPrec rp1 rl1) (liftReadList rp1 rl1) + rp1 rl1 0 s3 + ("}", s5) <- lex s4 + return (In x, s5) + +instance Show2 p => Show1 (Fix p) where + liftShowsPrec sp1 sl1 p (In x) = showParen (p > 10) $ + showString "In {out = " + . liftShowsPrec2 (liftShowsPrec sp1 sl1) (liftShowList sp1 sl1) + sp1 sl1 0 x + . showChar '}' +#endif + +instance Bifunctor p => Functor (Fix p) where + fmap f (In p) = In (bimap (fmap f) f p) + {-# INLINE fmap #-} + +instance Biapplicative p => Applicative (Fix p) where + pure a = In (bipure (pure a) a) + {-# INLINE pure #-} + In p <*> In q = In (biliftA2 (<*>) ($) p q) + {-# INLINE (<*>) #-} + +instance Bifoldable p => Foldable (Fix p) where + foldMap f (In p) = bifoldMap (foldMap f) f p + {-# INLINE foldMap #-} + +instance Bitraversable p => Traversable (Fix p) where + traverse f (In p) = In <$> bitraverse (traverse f) f p + {-# INLINE traverse #-} diff --git a/src/Data/Bifunctor/Flip.hs b/src/Data/Bifunctor/Flip.hs --- a/src/Data/Bifunctor/Flip.hs +++ b/src/Data/Bifunctor/Flip.hs @@ -1,139 +1,139 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - -#if __GLASGOW_HASKELL__ >= 704 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif -#include "bifunctors-common.h" - ------------------------------------------------------------------------------ --- | --- Module : Data.Bifunctor.Flip --- Copyright : (C) 2008-2016 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bifunctor.Flip - ( Flip(..) - ) where - -#if __GLASGOW_HASKELL__ < 710 -import Control.Applicative -#endif - -import Data.Biapplicative -import Data.Bifoldable -import Data.Bifunctor.Functor -import Data.Bitraversable - -#if __GLASGOW_HASKELL__ < 710 -import Data.Foldable -import Data.Monoid -import Data.Traversable -#endif - -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif - -#if LIFTED_FUNCTOR_CLASSES -import Data.Functor.Classes -#endif - --- | Make a 'Bifunctor' flipping the arguments of a 'Bifunctor'. -newtype Flip p a b = Flip { runFlip :: p b a } - deriving ( Eq, Ord, Show, Read -#if __GLASGOW_HASKELL__ >= 702 - , Generic -#endif -#if __GLASGOW_HASKELL__ >= 708 - , Typeable -#endif - ) - -#if LIFTED_FUNCTOR_CLASSES -instance (Eq2 p, Eq a) => Eq1 (Flip p a) where - liftEq = liftEq2 (==) -instance Eq2 p => Eq2 (Flip p) where - liftEq2 f g (Flip x) (Flip y) = liftEq2 g f x y - -instance (Ord2 p, Ord a) => Ord1 (Flip p a) where - liftCompare = liftCompare2 compare -instance Ord2 p => Ord2 (Flip p) where - liftCompare2 f g (Flip x) (Flip y) = liftCompare2 g f x y - -instance (Read2 p, Read a) => Read1 (Flip p a) where - liftReadsPrec = liftReadsPrec2 readsPrec readList -instance Read2 p => Read2 (Flip p) where - liftReadsPrec2 rp1 rl1 rp2 rl2 p = readParen (p > 10) $ \s0 -> do - ("Flip", s1) <- lex s0 - ("{", s2) <- lex s1 - ("runFlip", s3) <- lex s2 - (x, s4) <- liftReadsPrec2 rp2 rl2 rp1 rl1 0 s3 - ("}", s5) <- lex s4 - return (Flip x, s5) - -instance (Show2 p, Show a) => Show1 (Flip p a) where - liftShowsPrec = liftShowsPrec2 showsPrec showList -instance Show2 p => Show2 (Flip p) where - liftShowsPrec2 sp1 sl1 sp2 sl2 p (Flip x) = showParen (p > 10) $ - showString "Flip {runFlip = " - . liftShowsPrec2 sp2 sl2 sp1 sl1 0 x - . showChar '}' -#endif - -instance Bifunctor p => Bifunctor (Flip p) where - first f = Flip . second f . runFlip - {-# INLINE first #-} - second f = Flip . first f . runFlip - {-# INLINE second #-} - bimap f g = Flip . bimap g f . runFlip - {-# INLINE bimap #-} - -instance Bifunctor p => Functor (Flip p a) where - fmap f = Flip . first f . runFlip - {-# INLINE fmap #-} - -instance Biapplicative p => Biapplicative (Flip p) where - bipure a b = Flip (bipure b a) - {-# INLINE bipure #-} - - Flip fg <<*>> Flip xy = Flip (fg <<*>> xy) - {-# INLINE (<<*>>) #-} - -instance Bifoldable p => Bifoldable (Flip p) where - bifoldMap f g = bifoldMap g f . runFlip - {-# INLINE bifoldMap #-} - -instance Bifoldable p => Foldable (Flip p a) where - foldMap f = bifoldMap f (const mempty) . runFlip - {-# INLINE foldMap #-} - -instance Bitraversable p => Bitraversable (Flip p) where - bitraverse f g = fmap Flip . bitraverse g f . runFlip - {-# INLINE bitraverse #-} - -instance Bitraversable p => Traversable (Flip p a) where - traverse f = fmap Flip . bitraverse f pure . runFlip - {-# INLINE traverse #-} - -instance BifunctorFunctor Flip where - bifmap f (Flip p) = Flip (f p) +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +#if __GLASGOW_HASKELL__ >= 704 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif +#include "bifunctors-common.h" + +----------------------------------------------------------------------------- +-- | +-- Module : Data.Bifunctor.Flip +-- Copyright : (C) 2008-2016 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +---------------------------------------------------------------------------- +module Data.Bifunctor.Flip + ( Flip(..) + ) where + +#if __GLASGOW_HASKELL__ < 710 +import Control.Applicative +#endif + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bifunctor.Functor +import Data.Bitraversable + +#if __GLASGOW_HASKELL__ < 710 +import Data.Foldable +import Data.Monoid +import Data.Traversable +#endif + +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif + +#if LIFTED_FUNCTOR_CLASSES +import Data.Functor.Classes +#endif + +-- | Make a 'Bifunctor' flipping the arguments of a 'Bifunctor'. +newtype Flip p a b = Flip { runFlip :: p b a } + deriving ( Eq, Ord, Show, Read +#if __GLASGOW_HASKELL__ >= 702 + , Generic +#endif +#if __GLASGOW_HASKELL__ >= 708 + , Typeable +#endif + ) + +#if LIFTED_FUNCTOR_CLASSES +instance (Eq2 p, Eq a) => Eq1 (Flip p a) where + liftEq = liftEq2 (==) +instance Eq2 p => Eq2 (Flip p) where + liftEq2 f g (Flip x) (Flip y) = liftEq2 g f x y + +instance (Ord2 p, Ord a) => Ord1 (Flip p a) where + liftCompare = liftCompare2 compare +instance Ord2 p => Ord2 (Flip p) where + liftCompare2 f g (Flip x) (Flip y) = liftCompare2 g f x y + +instance (Read2 p, Read a) => Read1 (Flip p a) where + liftReadsPrec = liftReadsPrec2 readsPrec readList +instance Read2 p => Read2 (Flip p) where + liftReadsPrec2 rp1 rl1 rp2 rl2 p = readParen (p > 10) $ \s0 -> do + ("Flip", s1) <- lex s0 + ("{", s2) <- lex s1 + ("runFlip", s3) <- lex s2 + (x, s4) <- liftReadsPrec2 rp2 rl2 rp1 rl1 0 s3 + ("}", s5) <- lex s4 + return (Flip x, s5) + +instance (Show2 p, Show a) => Show1 (Flip p a) where + liftShowsPrec = liftShowsPrec2 showsPrec showList +instance Show2 p => Show2 (Flip p) where + liftShowsPrec2 sp1 sl1 sp2 sl2 p (Flip x) = showParen (p > 10) $ + showString "Flip {runFlip = " + . liftShowsPrec2 sp2 sl2 sp1 sl1 0 x + . showChar '}' +#endif + +instance Bifunctor p => Bifunctor (Flip p) where + first f = Flip . second f . runFlip + {-# INLINE first #-} + second f = Flip . first f . runFlip + {-# INLINE second #-} + bimap f g = Flip . bimap g f . runFlip + {-# INLINE bimap #-} + +instance Bifunctor p => Functor (Flip p a) where + fmap f = Flip . first f . runFlip + {-# INLINE fmap #-} + +instance Biapplicative p => Biapplicative (Flip p) where + bipure a b = Flip (bipure b a) + {-# INLINE bipure #-} + + Flip fg <<*>> Flip xy = Flip (fg <<*>> xy) + {-# INLINE (<<*>>) #-} + +instance Bifoldable p => Bifoldable (Flip p) where + bifoldMap f g = bifoldMap g f . runFlip + {-# INLINE bifoldMap #-} + +instance Bifoldable p => Foldable (Flip p a) where + foldMap f = bifoldMap f (const mempty) . runFlip + {-# INLINE foldMap #-} + +instance Bitraversable p => Bitraversable (Flip p) where + bitraverse f g = fmap Flip . bitraverse g f . runFlip + {-# INLINE bitraverse #-} + +instance Bitraversable p => Traversable (Flip p a) where + traverse f = fmap Flip . bitraverse f pure . runFlip + {-# INLINE traverse #-} + +instance BifunctorFunctor Flip where + bifmap f (Flip p) = Flip (f p) diff --git a/src/Data/Bifunctor/Functor.hs b/src/Data/Bifunctor/Functor.hs --- a/src/Data/Bifunctor/Functor.hs +++ b/src/Data/Bifunctor/Functor.hs @@ -1,57 +1,57 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE RankNTypes #-} -{-# LANGUAGE TypeOperators #-} - -#if __GLASGOW_HASKELL__ >= 704 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif - -module Data.Bifunctor.Functor - ( (:->) - , BifunctorFunctor(..) - , BifunctorMonad(..) - , biliftM - , BifunctorComonad(..) - , biliftW - ) where - --- | Using parametricity as an approximation of a natural transformation in two arguments. -type (:->) p q = forall a b. p a b -> q a b -infixr 0 :-> - -class BifunctorFunctor t where - bifmap :: (p :-> q) -> t p :-> t q - -class BifunctorFunctor t => BifunctorMonad t where - bireturn :: p :-> t p - bibind :: (p :-> t q) -> t p :-> t q - bibind f = bijoin . bifmap f - bijoin :: t (t p) :-> t p - bijoin = bibind id -#if __GLASGOW_HASKELL__ >= 708 - {-# MINIMAL bireturn, (bibind | bijoin) #-} -#endif - -biliftM :: BifunctorMonad t => (p :-> q) -> t p :-> t q -biliftM f = bibind (bireturn . f) -{-# INLINE biliftM #-} - -class BifunctorFunctor t => BifunctorComonad t where - biextract :: t p :-> p - biextend :: (t p :-> q) -> t p :-> t q - biextend f = bifmap f . biduplicate - biduplicate :: t p :-> t (t p) - biduplicate = biextend id -#if __GLASGOW_HASKELL__ >= 708 - {-# MINIMAL biextract, (biextend | biduplicate) #-} -#endif - -biliftW :: BifunctorComonad t => (p :-> q) -> t p :-> t q -biliftW f = biextend (f . biextract) -{-# INLINE biliftW #-} +{-# LANGUAGE CPP #-} +{-# LANGUAGE RankNTypes #-} +{-# LANGUAGE TypeOperators #-} + +#if __GLASGOW_HASKELL__ >= 704 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif + +module Data.Bifunctor.Functor + ( (:->) + , BifunctorFunctor(..) + , BifunctorMonad(..) + , biliftM + , BifunctorComonad(..) + , biliftW + ) where + +-- | Using parametricity as an approximation of a natural transformation in two arguments. +type (:->) p q = forall a b. p a b -> q a b +infixr 0 :-> + +class BifunctorFunctor t where + bifmap :: (p :-> q) -> t p :-> t q + +class BifunctorFunctor t => BifunctorMonad t where + bireturn :: p :-> t p + bibind :: (p :-> t q) -> t p :-> t q + bibind f = bijoin . bifmap f + bijoin :: t (t p) :-> t p + bijoin = bibind id +#if __GLASGOW_HASKELL__ >= 708 + {-# MINIMAL bireturn, (bibind | bijoin) #-} +#endif + +biliftM :: BifunctorMonad t => (p :-> q) -> t p :-> t q +biliftM f = bibind (bireturn . f) +{-# INLINE biliftM #-} + +class BifunctorFunctor t => BifunctorComonad t where + biextract :: t p :-> p + biextend :: (t p :-> q) -> t p :-> t q + biextend f = bifmap f . biduplicate + biduplicate :: t p :-> t (t p) + biduplicate = biextend id +#if __GLASGOW_HASKELL__ >= 708 + {-# MINIMAL biextract, (biextend | biduplicate) #-} +#endif + +biliftW :: BifunctorComonad t => (p :-> q) -> t p :-> t q +biliftW f = biextend (f . biextract) +{-# INLINE biliftW #-} diff --git a/src/Data/Bifunctor/Join.hs b/src/Data/Bifunctor/Join.hs --- a/src/Data/Bifunctor/Join.hs +++ b/src/Data/Bifunctor/Join.hs @@ -1,123 +1,123 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE FlexibleContexts #-} -{-# LANGUAGE StandaloneDeriving #-} -{-# LANGUAGE UndecidableInstances #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - -#if __GLASGOW_HASKELL__ >= 704 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif -#include "bifunctors-common.h" - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2008-2016 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : non-portable --- ----------------------------------------------------------------------------- -module Data.Bifunctor.Join - ( Join(..) - ) where - -#if __GLASGOW_HASKELL__ < 710 -import Control.Applicative -#endif - -import Data.Biapplicative -import Data.Bifoldable -import Data.Bitraversable - -#if __GLASGOW_HASKELL__ < 710 -import Data.Foldable -import Data.Traversable -#endif - -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif - -#if LIFTED_FUNCTOR_CLASSES -import Data.Functor.Classes -#endif - --- | Make a 'Functor' over both arguments of a 'Bifunctor'. -newtype Join p a = Join { runJoin :: p a a } - deriving - ( -#if __GLASGOW_HASKELL__ >= 702 - Generic -#endif -#if __GLASGOW_HASKELL__ >= 708 - , Typeable -#endif - ) - -deriving instance Eq (p a a) => Eq (Join p a) -deriving instance Ord (p a a) => Ord (Join p a) -deriving instance Show (p a a) => Show (Join p a) -deriving instance Read (p a a) => Read (Join p a) - -#if LIFTED_FUNCTOR_CLASSES -instance Eq2 p => Eq1 (Join p) where - liftEq f (Join x) (Join y) = liftEq2 f f x y - -instance Ord2 p => Ord1 (Join p) where - liftCompare f (Join x) (Join y) = liftCompare2 f f x y - -instance Read2 p => Read1 (Join p) where - liftReadsPrec rp1 rl1 p = readParen (p > 10) $ \s0 -> do - ("Join", s1) <- lex s0 - ("{", s2) <- lex s1 - ("runJoin", s3) <- lex s2 - (x, s4) <- liftReadsPrec2 rp1 rl1 rp1 rl1 0 s3 - ("}", s5) <- lex s4 - return (Join x, s5) - -instance Show2 p => Show1 (Join p) where - liftShowsPrec sp1 sl1 p (Join x) = showParen (p > 10) $ - showString "Join {runJoin = " - . liftShowsPrec2 sp1 sl1 sp1 sl1 0 x - . showChar '}' -#endif - -instance Bifunctor p => Functor (Join p) where - fmap f (Join a) = Join (bimap f f a) - {-# INLINE fmap #-} - -instance Biapplicative p => Applicative (Join p) where - pure a = Join (bipure a a) - {-# INLINE pure #-} - Join f <*> Join a = Join (f <<*>> a) - {-# INLINE (<*>) #-} - Join a *> Join b = Join (a *>> b) - {-# INLINE (*>) #-} - Join a <* Join b = Join (a <<* b) - {-# INLINE (<*) #-} - -instance Bifoldable p => Foldable (Join p) where - foldMap f (Join a) = bifoldMap f f a - {-# INLINE foldMap #-} - -instance Bitraversable p => Traversable (Join p) where - traverse f (Join a) = fmap Join (bitraverse f f a) - {-# INLINE traverse #-} - sequenceA (Join a) = fmap Join (bisequenceA a) - {-# INLINE sequenceA #-} +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE UndecidableInstances #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +#if __GLASGOW_HASKELL__ >= 704 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif +#include "bifunctors-common.h" + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2008-2016 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : non-portable +-- +---------------------------------------------------------------------------- +module Data.Bifunctor.Join + ( Join(..) + ) where + +#if __GLASGOW_HASKELL__ < 710 +import Control.Applicative +#endif + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bitraversable + +#if __GLASGOW_HASKELL__ < 710 +import Data.Foldable +import Data.Traversable +#endif + +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif + +#if LIFTED_FUNCTOR_CLASSES +import Data.Functor.Classes +#endif + +-- | Make a 'Functor' over both arguments of a 'Bifunctor'. +newtype Join p a = Join { runJoin :: p a a } + deriving + ( +#if __GLASGOW_HASKELL__ >= 702 + Generic +#endif +#if __GLASGOW_HASKELL__ >= 708 + , Typeable +#endif + ) + +deriving instance Eq (p a a) => Eq (Join p a) +deriving instance Ord (p a a) => Ord (Join p a) +deriving instance Show (p a a) => Show (Join p a) +deriving instance Read (p a a) => Read (Join p a) + +#if LIFTED_FUNCTOR_CLASSES +instance Eq2 p => Eq1 (Join p) where + liftEq f (Join x) (Join y) = liftEq2 f f x y + +instance Ord2 p => Ord1 (Join p) where + liftCompare f (Join x) (Join y) = liftCompare2 f f x y + +instance Read2 p => Read1 (Join p) where + liftReadsPrec rp1 rl1 p = readParen (p > 10) $ \s0 -> do + ("Join", s1) <- lex s0 + ("{", s2) <- lex s1 + ("runJoin", s3) <- lex s2 + (x, s4) <- liftReadsPrec2 rp1 rl1 rp1 rl1 0 s3 + ("}", s5) <- lex s4 + return (Join x, s5) + +instance Show2 p => Show1 (Join p) where + liftShowsPrec sp1 sl1 p (Join x) = showParen (p > 10) $ + showString "Join {runJoin = " + . liftShowsPrec2 sp1 sl1 sp1 sl1 0 x + . showChar '}' +#endif + +instance Bifunctor p => Functor (Join p) where + fmap f (Join a) = Join (bimap f f a) + {-# INLINE fmap #-} + +instance Biapplicative p => Applicative (Join p) where + pure a = Join (bipure a a) + {-# INLINE pure #-} + Join f <*> Join a = Join (f <<*>> a) + {-# INLINE (<*>) #-} + Join a *> Join b = Join (a *>> b) + {-# INLINE (*>) #-} + Join a <* Join b = Join (a <<* b) + {-# INLINE (<*) #-} + +instance Bifoldable p => Foldable (Join p) where + foldMap f (Join a) = bifoldMap f f a + {-# INLINE foldMap #-} + +instance Bitraversable p => Traversable (Join p) where + traverse f (Join a) = fmap Join (bitraverse f f a) + {-# INLINE traverse #-} + sequenceA (Join a) = fmap Join (bisequenceA a) + {-# INLINE sequenceA #-} diff --git a/src/Data/Bifunctor/Joker.hs b/src/Data/Bifunctor/Joker.hs --- a/src/Data/Bifunctor/Joker.hs +++ b/src/Data/Bifunctor/Joker.hs @@ -1,191 +1,191 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE EmptyDataDecls #-} -{-# LANGUAGE TypeFamilies #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif - -#if __GLASGOW_HASKELL__ >= 708 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif -#include "bifunctors-common.h" - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2008-2016 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- --- From the Functional Pearl \"Clowns to the Left of me, Jokers to the Right: Dissecting Data Structures\" --- by Conor McBride. ----------------------------------------------------------------------------- -module Data.Bifunctor.Joker - ( Joker(..) - ) where - -#if __GLASGOW_HASKELL__ < 710 -import Control.Applicative -#endif - -import Data.Biapplicative -import Data.Bifoldable -import Data.Bitraversable -import Data.Functor.Classes - -#if __GLASGOW_HASKELL__ < 710 -import Data.Foldable -import Data.Traversable -#endif - -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif - --- | Make a 'Functor' over the second argument of a 'Bifunctor'. --- --- Mnemonic: C__l__owns to the __l__eft (parameter of the Bifunctor), --- joke__r__s to the __r__ight. -newtype Joker g a b = Joker { runJoker :: g b } - deriving ( Eq, Ord, Show, Read -#if __GLASGOW_HASKELL__ >= 702 - , Generic -#endif -#if __GLASGOW_HASKELL__ >= 708 - , Generic1 - , Typeable -#endif - ) - -#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 708 -data JokerMetaData -data JokerMetaCons -data JokerMetaSel - -instance Datatype JokerMetaData where - datatypeName _ = "Joker" - moduleName _ = "Data.Bifunctor.Joker" - -instance Constructor JokerMetaCons where - conName _ = "Joker" - conIsRecord _ = True - -instance Selector JokerMetaSel where - selName _ = "runJoker" - -instance Generic1 (Joker g a) where - type Rep1 (Joker g a) = D1 JokerMetaData (C1 JokerMetaCons - (S1 JokerMetaSel (Rec1 g))) - from1 = M1 . M1 . M1 . Rec1 . runJoker - to1 = Joker . unRec1 . unM1 . unM1 . unM1 -#endif - -#if LIFTED_FUNCTOR_CLASSES -instance Eq1 g => Eq1 (Joker g a) where - liftEq g = eqJoker (liftEq g) -instance Eq1 g => Eq2 (Joker g) where - liftEq2 _ g = eqJoker (liftEq g) - -instance Ord1 g => Ord1 (Joker g a) where - liftCompare g = compareJoker (liftCompare g) -instance Ord1 g => Ord2 (Joker g) where - liftCompare2 _ g = compareJoker (liftCompare g) - -instance Read1 g => Read1 (Joker g a) where - liftReadsPrec rp rl = readsPrecJoker (liftReadsPrec rp rl) -instance Read1 g => Read2 (Joker g) where - liftReadsPrec2 _ _ rp2 rl2 = readsPrecJoker (liftReadsPrec rp2 rl2) - -instance Show1 g => Show1 (Joker g a) where - liftShowsPrec sp sl = showsPrecJoker (liftShowsPrec sp sl) -instance Show1 g => Show2 (Joker g) where - liftShowsPrec2 _ _ sp2 sl2 = showsPrecJoker (liftShowsPrec sp2 sl2) -#else -instance Eq1 g => Eq1 (Joker g a) where - eq1 = eqJoker eq1 - -instance Ord1 g => Ord1 (Joker g a) where - compare1 = compareJoker compare1 - -instance Read1 g => Read1 (Joker g a) where - readsPrec1 = readsPrecJoker readsPrec1 - -instance Show1 g => Show1 (Joker g a) where - showsPrec1 = showsPrecJoker showsPrec1 -#endif - -eqJoker :: (g b1 -> g b2 -> Bool) - -> Joker g a1 b1 -> Joker g a2 b2 -> Bool -eqJoker eqB (Joker x) (Joker y) = eqB x y - -compareJoker :: (g b1 -> g b2 -> Ordering) - -> Joker g a1 b1 -> Joker g a2 b2 -> Ordering -compareJoker compareB (Joker x) (Joker y) = compareB x y - -readsPrecJoker :: (Int -> ReadS (g b)) - -> Int -> ReadS (Joker g a b) -readsPrecJoker rpB p = - readParen (p > 10) $ \s0 -> do - ("Joker", s1) <- lex s0 - ("{", s2) <- lex s1 - ("runJoker", s3) <- lex s2 - (x, s4) <- rpB 0 s3 - ("}", s5) <- lex s4 - return (Joker x, s5) - -showsPrecJoker :: (Int -> g b -> ShowS) - -> Int -> Joker g a b -> ShowS -showsPrecJoker spB p (Joker x) = - showParen (p > 10) $ - showString "Joker {runJoker = " - . spB 0 x - . showChar '}' - -instance Functor g => Bifunctor (Joker g) where - first _ = Joker . runJoker - {-# INLINE first #-} - second g = Joker . fmap g . runJoker - {-# INLINE second #-} - bimap _ g = Joker . fmap g . runJoker - {-# INLINE bimap #-} - -instance Functor g => Functor (Joker g a) where - fmap g = Joker . fmap g . runJoker - {-# INLINE fmap #-} - -instance Applicative g => Biapplicative (Joker g) where - bipure _ b = Joker (pure b) - {-# INLINE bipure #-} - - Joker mf <<*>> Joker mx = Joker (mf <*> mx) - {-# INLINE (<<*>>) #-} - -instance Foldable g => Bifoldable (Joker g) where - bifoldMap _ g = foldMap g . runJoker - {-# INLINE bifoldMap #-} - -instance Foldable g => Foldable (Joker g a) where - foldMap g = foldMap g . runJoker - {-# INLINE foldMap #-} - -instance Traversable g => Bitraversable (Joker g) where - bitraverse _ g = fmap Joker . traverse g . runJoker - {-# INLINE bitraverse #-} - -instance Traversable g => Traversable (Joker g a) where - traverse g = fmap Joker . traverse g . runJoker - {-# INLINE traverse #-} +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE TypeFamilies #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif + +#if __GLASGOW_HASKELL__ >= 708 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif +#include "bifunctors-common.h" + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2008-2016 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +-- From the Functional Pearl \"Clowns to the Left of me, Jokers to the Right: Dissecting Data Structures\" +-- by Conor McBride. +---------------------------------------------------------------------------- +module Data.Bifunctor.Joker + ( Joker(..) + ) where + +#if __GLASGOW_HASKELL__ < 710 +import Control.Applicative +#endif + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bitraversable +import Data.Functor.Classes + +#if __GLASGOW_HASKELL__ < 710 +import Data.Foldable +import Data.Traversable +#endif + +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif + +-- | Make a 'Functor' over the second argument of a 'Bifunctor'. +-- +-- Mnemonic: C__l__owns to the __l__eft (parameter of the Bifunctor), +-- joke__r__s to the __r__ight. +newtype Joker g a b = Joker { runJoker :: g b } + deriving ( Eq, Ord, Show, Read +#if __GLASGOW_HASKELL__ >= 702 + , Generic +#endif +#if __GLASGOW_HASKELL__ >= 708 + , Generic1 + , Typeable +#endif + ) + +#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 708 +data JokerMetaData +data JokerMetaCons +data JokerMetaSel + +instance Datatype JokerMetaData where + datatypeName _ = "Joker" + moduleName _ = "Data.Bifunctor.Joker" + +instance Constructor JokerMetaCons where + conName _ = "Joker" + conIsRecord _ = True + +instance Selector JokerMetaSel where + selName _ = "runJoker" + +instance Generic1 (Joker g a) where + type Rep1 (Joker g a) = D1 JokerMetaData (C1 JokerMetaCons + (S1 JokerMetaSel (Rec1 g))) + from1 = M1 . M1 . M1 . Rec1 . runJoker + to1 = Joker . unRec1 . unM1 . unM1 . unM1 +#endif + +#if LIFTED_FUNCTOR_CLASSES +instance Eq1 g => Eq1 (Joker g a) where + liftEq g = eqJoker (liftEq g) +instance Eq1 g => Eq2 (Joker g) where + liftEq2 _ g = eqJoker (liftEq g) + +instance Ord1 g => Ord1 (Joker g a) where + liftCompare g = compareJoker (liftCompare g) +instance Ord1 g => Ord2 (Joker g) where + liftCompare2 _ g = compareJoker (liftCompare g) + +instance Read1 g => Read1 (Joker g a) where + liftReadsPrec rp rl = readsPrecJoker (liftReadsPrec rp rl) +instance Read1 g => Read2 (Joker g) where + liftReadsPrec2 _ _ rp2 rl2 = readsPrecJoker (liftReadsPrec rp2 rl2) + +instance Show1 g => Show1 (Joker g a) where + liftShowsPrec sp sl = showsPrecJoker (liftShowsPrec sp sl) +instance Show1 g => Show2 (Joker g) where + liftShowsPrec2 _ _ sp2 sl2 = showsPrecJoker (liftShowsPrec sp2 sl2) +#else +instance Eq1 g => Eq1 (Joker g a) where + eq1 = eqJoker eq1 + +instance Ord1 g => Ord1 (Joker g a) where + compare1 = compareJoker compare1 + +instance Read1 g => Read1 (Joker g a) where + readsPrec1 = readsPrecJoker readsPrec1 + +instance Show1 g => Show1 (Joker g a) where + showsPrec1 = showsPrecJoker showsPrec1 +#endif + +eqJoker :: (g b1 -> g b2 -> Bool) + -> Joker g a1 b1 -> Joker g a2 b2 -> Bool +eqJoker eqB (Joker x) (Joker y) = eqB x y + +compareJoker :: (g b1 -> g b2 -> Ordering) + -> Joker g a1 b1 -> Joker g a2 b2 -> Ordering +compareJoker compareB (Joker x) (Joker y) = compareB x y + +readsPrecJoker :: (Int -> ReadS (g b)) + -> Int -> ReadS (Joker g a b) +readsPrecJoker rpB p = + readParen (p > 10) $ \s0 -> do + ("Joker", s1) <- lex s0 + ("{", s2) <- lex s1 + ("runJoker", s3) <- lex s2 + (x, s4) <- rpB 0 s3 + ("}", s5) <- lex s4 + return (Joker x, s5) + +showsPrecJoker :: (Int -> g b -> ShowS) + -> Int -> Joker g a b -> ShowS +showsPrecJoker spB p (Joker x) = + showParen (p > 10) $ + showString "Joker {runJoker = " + . spB 0 x + . showChar '}' + +instance Functor g => Bifunctor (Joker g) where + first _ = Joker . runJoker + {-# INLINE first #-} + second g = Joker . fmap g . runJoker + {-# INLINE second #-} + bimap _ g = Joker . fmap g . runJoker + {-# INLINE bimap #-} + +instance Functor g => Functor (Joker g a) where + fmap g = Joker . fmap g . runJoker + {-# INLINE fmap #-} + +instance Applicative g => Biapplicative (Joker g) where + bipure _ b = Joker (pure b) + {-# INLINE bipure #-} + + Joker mf <<*>> Joker mx = Joker (mf <*> mx) + {-# INLINE (<<*>>) #-} + +instance Foldable g => Bifoldable (Joker g) where + bifoldMap _ g = foldMap g . runJoker + {-# INLINE bifoldMap #-} + +instance Foldable g => Foldable (Joker g a) where + foldMap g = foldMap g . runJoker + {-# INLINE foldMap #-} + +instance Traversable g => Bitraversable (Joker g) where + bitraverse _ g = fmap Joker . traverse g . runJoker + {-# INLINE bitraverse #-} + +instance Traversable g => Traversable (Joker g a) where + traverse g = fmap Joker . traverse g . runJoker + {-# INLINE traverse #-} diff --git a/src/Data/Bifunctor/Product.hs b/src/Data/Bifunctor/Product.hs --- a/src/Data/Bifunctor/Product.hs +++ b/src/Data/Bifunctor/Product.hs @@ -1,180 +1,187 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE EmptyDataDecls #-} -{-# LANGUAGE TypeFamilies #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif - -#if __GLASGOW_HASKELL__ >= 708 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif -#include "bifunctors-common.h" - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2008-2016 Jesse Selover, Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- --- The product of two bifunctors. ----------------------------------------------------------------------------- -module Data.Bifunctor.Product - ( Product(..) - ) where - -#if __GLASGOW_HASKELL__ < 710 -import Control.Applicative -#endif - -import qualified Control.Arrow as A -import Control.Category -import Data.Biapplicative -import Data.Bifoldable -import Data.Bifunctor.Functor -import Data.Bitraversable - -#if __GLASGOW_HASKELL__ < 710 -import Data.Monoid hiding (Product) -#endif - -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif - -#if LIFTED_FUNCTOR_CLASSES -import Data.Functor.Classes -#endif - -import Prelude hiding ((.),id) - --- | Form the product of two bifunctors -data Product f g a b = Pair (f a b) (g a b) - deriving ( Eq, Ord, Show, Read -#if __GLASGOW_HASKELL__ >= 702 - , Generic -#endif -#if __GLASGOW_HASKELL__ >= 708 - , Generic1 - , Typeable -#endif - ) - -#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 708 -data ProductMetaData -data ProductMetaCons - -instance Datatype ProductMetaData where - datatypeName _ = "Product" - moduleName _ = "Data.Bifunctor.Product" - -instance Constructor ProductMetaCons where - conName _ = "Pair" - -instance Generic1 (Product f g a) where - type Rep1 (Product f g a) = D1 ProductMetaData (C1 ProductMetaCons ((:*:) - (S1 NoSelector (Rec1 (f a))) - (S1 NoSelector (Rec1 (g a))))) - from1 (Pair f g) = M1 (M1 (M1 (Rec1 f) :*: M1 (Rec1 g))) - to1 (M1 (M1 (M1 f :*: M1 g))) = Pair (unRec1 f) (unRec1 g) -#endif - -#if LIFTED_FUNCTOR_CLASSES -instance (Eq2 f, Eq2 g, Eq a) => Eq1 (Product f g a) where - liftEq = liftEq2 (==) -instance (Eq2 f, Eq2 g) => Eq2 (Product f g) where - liftEq2 f g (Pair x1 y1) (Pair x2 y2) = - liftEq2 f g x1 x2 && liftEq2 f g y1 y2 - -instance (Ord2 f, Ord2 g, Ord a) => Ord1 (Product f g a) where - liftCompare = liftCompare2 compare -instance (Ord2 f, Ord2 g) => Ord2 (Product f g) where - liftCompare2 f g (Pair x1 y1) (Pair x2 y2) = - liftCompare2 f g x1 x2 `mappend` liftCompare2 f g y1 y2 - -instance (Read2 f, Read2 g, Read a) => Read1 (Product f g a) where - liftReadsPrec = liftReadsPrec2 readsPrec readList -instance (Read2 f, Read2 g) => Read2 (Product f g) where - liftReadsPrec2 rp1 rl1 rp2 rl2 = readsData $ - readsBinaryWith (liftReadsPrec2 rp1 rl1 rp2 rl2) - (liftReadsPrec2 rp1 rl1 rp2 rl2) - "Pair" Pair - -instance (Show2 f, Show2 g, Show a) => Show1 (Product f g a) where - liftShowsPrec = liftShowsPrec2 showsPrec showList -instance (Show2 f, Show2 g) => Show2 (Product f g) where - liftShowsPrec2 sp1 sl1 sp2 sl2 p (Pair x y) = - showsBinaryWith (liftShowsPrec2 sp1 sl1 sp2 sl2) - (liftShowsPrec2 sp1 sl1 sp2 sl2) - "Pair" p x y -#endif - -instance (Bifunctor f, Bifunctor g) => Bifunctor (Product f g) where - first f (Pair x y) = Pair (first f x) (first f y) - {-# INLINE first #-} - second g (Pair x y) = Pair (second g x) (second g y) - {-# INLINE second #-} - bimap f g (Pair x y) = Pair (bimap f g x) (bimap f g y) - {-# INLINE bimap #-} - -instance (Biapplicative f, Biapplicative g) => Biapplicative (Product f g) where - bipure a b = Pair (bipure a b) (bipure a b) - {-# INLINE bipure #-} - Pair w x <<*>> Pair y z = Pair (w <<*>> y) (x <<*>> z) - {-# INLINE (<<*>>) #-} - -instance (Bifoldable f, Bifoldable g) => Bifoldable (Product f g) where - bifoldMap f g (Pair x y) = bifoldMap f g x `mappend` bifoldMap f g y - {-# INLINE bifoldMap #-} - -instance (Bitraversable f, Bitraversable g) => Bitraversable (Product f g) where - bitraverse f g (Pair x y) = Pair <$> bitraverse f g x <*> bitraverse f g y - {-# INLINE bitraverse #-} - -instance BifunctorFunctor (Product p) where - bifmap f (Pair p q) = Pair p (f q) - -instance BifunctorComonad (Product p) where - biextract (Pair _ q) = q - biduplicate pq@(Pair p _) = Pair p pq - biextend f pq@(Pair p _) = Pair p (f pq) - -instance (Category p, Category q) => Category (Product p q) where - id = Pair id id - Pair x y . Pair x' y' = Pair (x . x') (y . y') - -instance (A.Arrow p, A.Arrow q) => A.Arrow (Product p q) where - arr f = Pair (A.arr f) (A.arr f) - first (Pair x y) = Pair (A.first x) (A.first y) - second (Pair x y) = Pair (A.second x) (A.second y) - Pair x y *** Pair x' y' = Pair (x A.*** x') (y A.*** y') - Pair x y &&& Pair x' y' = Pair (x A.&&& x') (y A.&&& y') - -instance (A.ArrowChoice p, A.ArrowChoice q) => A.ArrowChoice (Product p q) where - left (Pair x y) = Pair (A.left x) (A.left y) - right (Pair x y) = Pair (A.right x) (A.right y) - Pair x y +++ Pair x' y' = Pair (x A.+++ x') (y A.+++ y') - Pair x y ||| Pair x' y' = Pair (x A.||| x') (y A.||| y') - -instance (A.ArrowLoop p, A.ArrowLoop q) => A.ArrowLoop (Product p q) where - loop (Pair x y) = Pair (A.loop x) (A.loop y) - -instance (A.ArrowZero p, A.ArrowZero q) => A.ArrowZero (Product p q) where - zeroArrow = Pair A.zeroArrow A.zeroArrow - -instance (A.ArrowPlus p, A.ArrowPlus q) => A.ArrowPlus (Product p q) where - Pair x y <+> Pair x' y' = Pair (x A.<+> x') (y A.<+> y') +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE DeriveFoldable #-} +{-# LANGUAGE DeriveFunctor #-} +{-# LANGUAGE DeriveTraversable #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE TypeFamilies #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif + +#if __GLASGOW_HASKELL__ >= 708 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif +#include "bifunctors-common.h" + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2008-2016 Jesse Selover, Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +-- The product of two bifunctors. +---------------------------------------------------------------------------- +module Data.Bifunctor.Product + ( Product(..) + ) where + +import qualified Control.Arrow as A +import Control.Category +import Data.Biapplicative +import Data.Bifoldable +import Data.Bifunctor.Functor +import Data.Bitraversable + +#if __GLASGOW_HASKELL__ < 710 +import Control.Applicative +import Data.Foldable +import Data.Monoid hiding (Product) +import Data.Traversable +#endif + +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif + +#if LIFTED_FUNCTOR_CLASSES +import Data.Functor.Classes +#endif + +import Prelude hiding ((.),id) + +-- | Form the product of two bifunctors +data Product f g a b = Pair (f a b) (g a b) + deriving ( Eq, Ord, Show, Read +#if __GLASGOW_HASKELL__ >= 702 + , Generic +#endif +#if __GLASGOW_HASKELL__ >= 708 + , Generic1 + , Typeable +#endif + ) +deriving instance (Functor (f a), Functor (g a)) => Functor (Product f g a) +deriving instance (Foldable (f a), Foldable (g a)) => Foldable (Product f g a) +deriving instance (Traversable (f a), Traversable (g a)) => Traversable (Product f g a) + +#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 708 +data ProductMetaData +data ProductMetaCons + +instance Datatype ProductMetaData where + datatypeName _ = "Product" + moduleName _ = "Data.Bifunctor.Product" + +instance Constructor ProductMetaCons where + conName _ = "Pair" + +instance Generic1 (Product f g a) where + type Rep1 (Product f g a) = D1 ProductMetaData (C1 ProductMetaCons ((:*:) + (S1 NoSelector (Rec1 (f a))) + (S1 NoSelector (Rec1 (g a))))) + from1 (Pair f g) = M1 (M1 (M1 (Rec1 f) :*: M1 (Rec1 g))) + to1 (M1 (M1 (M1 f :*: M1 g))) = Pair (unRec1 f) (unRec1 g) +#endif + +#if LIFTED_FUNCTOR_CLASSES +instance (Eq2 f, Eq2 g, Eq a) => Eq1 (Product f g a) where + liftEq = liftEq2 (==) +instance (Eq2 f, Eq2 g) => Eq2 (Product f g) where + liftEq2 f g (Pair x1 y1) (Pair x2 y2) = + liftEq2 f g x1 x2 && liftEq2 f g y1 y2 + +instance (Ord2 f, Ord2 g, Ord a) => Ord1 (Product f g a) where + liftCompare = liftCompare2 compare +instance (Ord2 f, Ord2 g) => Ord2 (Product f g) where + liftCompare2 f g (Pair x1 y1) (Pair x2 y2) = + liftCompare2 f g x1 x2 `mappend` liftCompare2 f g y1 y2 + +instance (Read2 f, Read2 g, Read a) => Read1 (Product f g a) where + liftReadsPrec = liftReadsPrec2 readsPrec readList +instance (Read2 f, Read2 g) => Read2 (Product f g) where + liftReadsPrec2 rp1 rl1 rp2 rl2 = readsData $ + readsBinaryWith (liftReadsPrec2 rp1 rl1 rp2 rl2) + (liftReadsPrec2 rp1 rl1 rp2 rl2) + "Pair" Pair + +instance (Show2 f, Show2 g, Show a) => Show1 (Product f g a) where + liftShowsPrec = liftShowsPrec2 showsPrec showList +instance (Show2 f, Show2 g) => Show2 (Product f g) where + liftShowsPrec2 sp1 sl1 sp2 sl2 p (Pair x y) = + showsBinaryWith (liftShowsPrec2 sp1 sl1 sp2 sl2) + (liftShowsPrec2 sp1 sl1 sp2 sl2) + "Pair" p x y +#endif + +instance (Bifunctor f, Bifunctor g) => Bifunctor (Product f g) where + first f (Pair x y) = Pair (first f x) (first f y) + {-# INLINE first #-} + second g (Pair x y) = Pair (second g x) (second g y) + {-# INLINE second #-} + bimap f g (Pair x y) = Pair (bimap f g x) (bimap f g y) + {-# INLINE bimap #-} + +instance (Biapplicative f, Biapplicative g) => Biapplicative (Product f g) where + bipure a b = Pair (bipure a b) (bipure a b) + {-# INLINE bipure #-} + Pair w x <<*>> Pair y z = Pair (w <<*>> y) (x <<*>> z) + {-# INLINE (<<*>>) #-} + +instance (Bifoldable f, Bifoldable g) => Bifoldable (Product f g) where + bifoldMap f g (Pair x y) = bifoldMap f g x `mappend` bifoldMap f g y + {-# INLINE bifoldMap #-} + +instance (Bitraversable f, Bitraversable g) => Bitraversable (Product f g) where + bitraverse f g (Pair x y) = Pair <$> bitraverse f g x <*> bitraverse f g y + {-# INLINE bitraverse #-} + +instance BifunctorFunctor (Product p) where + bifmap f (Pair p q) = Pair p (f q) + +instance BifunctorComonad (Product p) where + biextract (Pair _ q) = q + biduplicate pq@(Pair p _) = Pair p pq + biextend f pq@(Pair p _) = Pair p (f pq) + +instance (Category p, Category q) => Category (Product p q) where + id = Pair id id + Pair x y . Pair x' y' = Pair (x . x') (y . y') + +instance (A.Arrow p, A.Arrow q) => A.Arrow (Product p q) where + arr f = Pair (A.arr f) (A.arr f) + first (Pair x y) = Pair (A.first x) (A.first y) + second (Pair x y) = Pair (A.second x) (A.second y) + Pair x y *** Pair x' y' = Pair (x A.*** x') (y A.*** y') + Pair x y &&& Pair x' y' = Pair (x A.&&& x') (y A.&&& y') + +instance (A.ArrowChoice p, A.ArrowChoice q) => A.ArrowChoice (Product p q) where + left (Pair x y) = Pair (A.left x) (A.left y) + right (Pair x y) = Pair (A.right x) (A.right y) + Pair x y +++ Pair x' y' = Pair (x A.+++ x') (y A.+++ y') + Pair x y ||| Pair x' y' = Pair (x A.||| x') (y A.||| y') + +instance (A.ArrowLoop p, A.ArrowLoop q) => A.ArrowLoop (Product p q) where + loop (Pair x y) = Pair (A.loop x) (A.loop y) + +instance (A.ArrowZero p, A.ArrowZero q) => A.ArrowZero (Product p q) where + zeroArrow = Pair A.zeroArrow A.zeroArrow + +instance (A.ArrowPlus p, A.ArrowPlus q) => A.ArrowPlus (Product p q) where + Pair x y <+> Pair x' y' = Pair (x A.<+> x') (y A.<+> y') diff --git a/src/Data/Bifunctor/Sum.hs b/src/Data/Bifunctor/Sum.hs --- a/src/Data/Bifunctor/Sum.hs +++ b/src/Data/Bifunctor/Sum.hs @@ -1,136 +1,146 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE EmptyDataDecls #-} -{-# LANGUAGE TypeFamilies #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif - -#if __GLASGOW_HASKELL__ >= 708 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif -#include "bifunctors-common.h" - -module Data.Bifunctor.Sum where - -import Data.Bifunctor -import Data.Bifunctor.Functor -import Data.Bifoldable -import Data.Bitraversable - -#if __GLASGOW_HASKELL__ < 710 -import Data.Functor -import Data.Monoid hiding (Sum) -#endif -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif -#if LIFTED_FUNCTOR_CLASSES -import Data.Functor.Classes -#endif - -data Sum p q a b = L2 (p a b) | R2 (q a b) - deriving ( Eq, Ord, Show, Read -#if __GLASGOW_HASKELL__ >= 702 - , Generic -#endif -#if __GLASGOW_HASKELL__ >= 708 - , Generic1 - , Typeable -#endif - ) - -#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 708 -data SumMetaData -data SumMetaConsL2 -data SumMetaConsR2 - -instance Datatype SumMetaData where - datatypeName _ = "Sum" - moduleName _ = "Data.Bifunctor.Sum" - -instance Constructor SumMetaConsL2 where - conName _ = "L2" - -instance Constructor SumMetaConsR2 where - conName _ = "R2" - -instance Generic1 (Sum p q a) where - type Rep1 (Sum p q a) = D1 SumMetaData ((:+:) - (C1 SumMetaConsL2 (S1 NoSelector (Rec1 (p a)))) - (C1 SumMetaConsR2 (S1 NoSelector (Rec1 (q a))))) - from1 (L2 p) = M1 (L1 (M1 (M1 (Rec1 p)))) - from1 (R2 q) = M1 (R1 (M1 (M1 (Rec1 q)))) - to1 (M1 (L1 (M1 (M1 p)))) = L2 (unRec1 p) - to1 (M1 (R1 (M1 (M1 q)))) = R2 (unRec1 q) -#endif - -#if LIFTED_FUNCTOR_CLASSES -instance (Eq2 f, Eq2 g, Eq a) => Eq1 (Sum f g a) where - liftEq = liftEq2 (==) -instance (Eq2 f, Eq2 g) => Eq2 (Sum f g) where - liftEq2 f g (L2 x1) (L2 x2) = liftEq2 f g x1 x2 - liftEq2 _ _ (L2 _) (R2 _) = False - liftEq2 _ _ (R2 _) (L2 _) = False - liftEq2 f g (R2 y1) (R2 y2) = liftEq2 f g y1 y2 - -instance (Ord2 f, Ord2 g, Ord a) => Ord1 (Sum f g a) where - liftCompare = liftCompare2 compare -instance (Ord2 f, Ord2 g) => Ord2 (Sum f g) where - liftCompare2 f g (L2 x1) (L2 x2) = liftCompare2 f g x1 x2 - liftCompare2 _ _ (L2 _) (R2 _) = LT - liftCompare2 _ _ (R2 _) (L2 _) = GT - liftCompare2 f g (R2 y1) (R2 y2) = liftCompare2 f g y1 y2 - -instance (Read2 f, Read2 g, Read a) => Read1 (Sum f g a) where - liftReadsPrec = liftReadsPrec2 readsPrec readList -instance (Read2 f, Read2 g) => Read2 (Sum f g) where - liftReadsPrec2 rp1 rl1 rp2 rl2 = readsData $ - readsUnaryWith (liftReadsPrec2 rp1 rl1 rp2 rl2) "L2" L2 `mappend` - readsUnaryWith (liftReadsPrec2 rp1 rl1 rp2 rl2) "R2" R2 - -instance (Show2 f, Show2 g, Show a) => Show1 (Sum f g a) where - liftShowsPrec = liftShowsPrec2 showsPrec showList -instance (Show2 f, Show2 g) => Show2 (Sum f g) where - liftShowsPrec2 sp1 sl1 sp2 sl2 p (L2 x) = - showsUnaryWith (liftShowsPrec2 sp1 sl1 sp2 sl2) "L2" p x - liftShowsPrec2 sp1 sl1 sp2 sl2 p (R2 y) = - showsUnaryWith (liftShowsPrec2 sp1 sl1 sp2 sl2) "R2" p y -#endif - -instance (Bifunctor p, Bifunctor q) => Bifunctor (Sum p q) where - bimap f g (L2 p) = L2 (bimap f g p) - bimap f g (R2 q) = R2 (bimap f g q) - first f (L2 p) = L2 (first f p) - first f (R2 q) = R2 (first f q) - second f (L2 p) = L2 (second f p) - second f (R2 q) = R2 (second f q) - -instance (Bifoldable p, Bifoldable q) => Bifoldable (Sum p q) where - bifoldMap f g (L2 p) = bifoldMap f g p - bifoldMap f g (R2 q) = bifoldMap f g q - -instance (Bitraversable p, Bitraversable q) => Bitraversable (Sum p q) where - bitraverse f g (L2 p) = L2 <$> bitraverse f g p - bitraverse f g (R2 q) = R2 <$> bitraverse f g q - -instance BifunctorFunctor (Sum p) where - bifmap _ (L2 p) = L2 p - bifmap f (R2 q) = R2 (f q) - -instance BifunctorMonad (Sum p) where - bireturn = R2 - bijoin (L2 p) = L2 p - bijoin (R2 q) = q - bibind _ (L2 p) = L2 p - bibind f (R2 q) = f q +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE DeriveFoldable #-} +{-# LANGUAGE DeriveFunctor #-} +{-# LANGUAGE DeriveTraversable #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE TypeFamilies #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif + +#if __GLASGOW_HASKELL__ >= 708 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif +#include "bifunctors-common.h" + +module Data.Bifunctor.Sum where + +import Data.Bifunctor +import Data.Bifunctor.Functor +import Data.Bifoldable +import Data.Bitraversable + +#if __GLASGOW_HASKELL__ < 710 +import Data.Foldable +import Data.Functor +import Data.Monoid hiding (Sum) +import Data.Traversable +#endif +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif +#if LIFTED_FUNCTOR_CLASSES +import Data.Functor.Classes +#endif + +data Sum p q a b = L2 (p a b) | R2 (q a b) + deriving ( Eq, Ord, Show, Read +#if __GLASGOW_HASKELL__ >= 702 + , Generic +#endif +#if __GLASGOW_HASKELL__ >= 708 + , Generic1 + , Typeable +#endif + ) +deriving instance (Functor (f a), Functor (g a)) => Functor (Sum f g a) +deriving instance (Foldable (f a), Foldable (g a)) => Foldable (Sum f g a) +deriving instance (Traversable (f a), Traversable (g a)) => Traversable (Sum f g a) + +#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 708 +data SumMetaData +data SumMetaConsL2 +data SumMetaConsR2 + +instance Datatype SumMetaData where + datatypeName _ = "Sum" + moduleName _ = "Data.Bifunctor.Sum" + +instance Constructor SumMetaConsL2 where + conName _ = "L2" + +instance Constructor SumMetaConsR2 where + conName _ = "R2" + +instance Generic1 (Sum p q a) where + type Rep1 (Sum p q a) = D1 SumMetaData ((:+:) + (C1 SumMetaConsL2 (S1 NoSelector (Rec1 (p a)))) + (C1 SumMetaConsR2 (S1 NoSelector (Rec1 (q a))))) + from1 (L2 p) = M1 (L1 (M1 (M1 (Rec1 p)))) + from1 (R2 q) = M1 (R1 (M1 (M1 (Rec1 q)))) + to1 (M1 (L1 (M1 (M1 p)))) = L2 (unRec1 p) + to1 (M1 (R1 (M1 (M1 q)))) = R2 (unRec1 q) +#endif + +#if LIFTED_FUNCTOR_CLASSES +instance (Eq2 f, Eq2 g, Eq a) => Eq1 (Sum f g a) where + liftEq = liftEq2 (==) +instance (Eq2 f, Eq2 g) => Eq2 (Sum f g) where + liftEq2 f g (L2 x1) (L2 x2) = liftEq2 f g x1 x2 + liftEq2 _ _ (L2 _) (R2 _) = False + liftEq2 _ _ (R2 _) (L2 _) = False + liftEq2 f g (R2 y1) (R2 y2) = liftEq2 f g y1 y2 + +instance (Ord2 f, Ord2 g, Ord a) => Ord1 (Sum f g a) where + liftCompare = liftCompare2 compare +instance (Ord2 f, Ord2 g) => Ord2 (Sum f g) where + liftCompare2 f g (L2 x1) (L2 x2) = liftCompare2 f g x1 x2 + liftCompare2 _ _ (L2 _) (R2 _) = LT + liftCompare2 _ _ (R2 _) (L2 _) = GT + liftCompare2 f g (R2 y1) (R2 y2) = liftCompare2 f g y1 y2 + +instance (Read2 f, Read2 g, Read a) => Read1 (Sum f g a) where + liftReadsPrec = liftReadsPrec2 readsPrec readList +instance (Read2 f, Read2 g) => Read2 (Sum f g) where + liftReadsPrec2 rp1 rl1 rp2 rl2 = readsData $ + readsUnaryWith (liftReadsPrec2 rp1 rl1 rp2 rl2) "L2" L2 `mappend` + readsUnaryWith (liftReadsPrec2 rp1 rl1 rp2 rl2) "R2" R2 + +instance (Show2 f, Show2 g, Show a) => Show1 (Sum f g a) where + liftShowsPrec = liftShowsPrec2 showsPrec showList +instance (Show2 f, Show2 g) => Show2 (Sum f g) where + liftShowsPrec2 sp1 sl1 sp2 sl2 p (L2 x) = + showsUnaryWith (liftShowsPrec2 sp1 sl1 sp2 sl2) "L2" p x + liftShowsPrec2 sp1 sl1 sp2 sl2 p (R2 y) = + showsUnaryWith (liftShowsPrec2 sp1 sl1 sp2 sl2) "R2" p y +#endif + +instance (Bifunctor p, Bifunctor q) => Bifunctor (Sum p q) where + bimap f g (L2 p) = L2 (bimap f g p) + bimap f g (R2 q) = R2 (bimap f g q) + first f (L2 p) = L2 (first f p) + first f (R2 q) = R2 (first f q) + second f (L2 p) = L2 (second f p) + second f (R2 q) = R2 (second f q) + +instance (Bifoldable p, Bifoldable q) => Bifoldable (Sum p q) where + bifoldMap f g (L2 p) = bifoldMap f g p + bifoldMap f g (R2 q) = bifoldMap f g q + +instance (Bitraversable p, Bitraversable q) => Bitraversable (Sum p q) where + bitraverse f g (L2 p) = L2 <$> bitraverse f g p + bitraverse f g (R2 q) = R2 <$> bitraverse f g q + +instance BifunctorFunctor (Sum p) where + bifmap _ (L2 p) = L2 p + bifmap f (R2 q) = R2 (f q) + +instance BifunctorMonad (Sum p) where + bireturn = R2 + bijoin (L2 p) = L2 p + bijoin (R2 q) = q + bibind _ (L2 p) = L2 p + bibind f (R2 q) = f q diff --git a/src/Data/Bifunctor/TH.hs b/src/Data/Bifunctor/TH.hs --- a/src/Data/Bifunctor/TH.hs +++ b/src/Data/Bifunctor/TH.hs @@ -1,1334 +1,1334 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE BangPatterns #-} -{-# LANGUAGE PatternGuards #-} -{-# LANGUAGE ScopedTypeVariables #-} - -#if __GLASGOW_HASKELL__ >= 704 -{-# LANGUAGE Unsafe #-} -#endif - -#ifndef MIN_VERSION_template_haskell -#define MIN_VERSION_template_haskell(x,y,z) 1 -#endif ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2008-2016 Edward Kmett, (C) 2015-2016 Ryan Scott --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- --- Functions to mechanically derive 'Bifunctor', 'Bifoldable', --- or 'Bitraversable' instances, or to splice their functions directly into --- source code. You need to enable the @TemplateHaskell@ language extension --- in order to use this module. ----------------------------------------------------------------------------- - -module Data.Bifunctor.TH ( - -- * @derive@- functions - -- $derive - -- * @make@- functions - -- $make - -- * 'Bifunctor' - deriveBifunctor - , deriveBifunctorOptions - , makeBimap - , makeBimapOptions - -- * 'Bifoldable' - , deriveBifoldable - , deriveBifoldableOptions - , makeBifold - , makeBifoldOptions - , makeBifoldMap - , makeBifoldMapOptions - , makeBifoldr - , makeBifoldrOptions - , makeBifoldl - , makeBifoldlOptions - -- * 'Bitraversable' - , deriveBitraversable - , deriveBitraversableOptions - , makeBitraverse - , makeBitraverseOptions - , makeBisequenceA - , makeBisequenceAOptions - , makeBimapM - , makeBimapMOptions - , makeBisequence - , makeBisequenceOptions - -- * 'Options' - , Options(..) - , defaultOptions - ) where - -import Control.Monad (guard, unless, when) - -import Data.Bifunctor.TH.Internal -import qualified Data.List as List -import qualified Data.Map as Map ((!), fromList, keys, lookup, member, size) -import Data.Maybe - -import Language.Haskell.TH.Datatype -import Language.Haskell.TH.Datatype.TyVarBndr -import Language.Haskell.TH.Lib -import Language.Haskell.TH.Ppr -import Language.Haskell.TH.Syntax - -------------------------------------------------------------------------------- --- User-facing API -------------------------------------------------------------------------------- - --- | Options that further configure how the functions in "Data.Bifunctor.TH" --- should behave. -newtype Options = Options - { emptyCaseBehavior :: Bool - -- ^ If 'True', derived instances for empty data types (i.e., ones with - -- no data constructors) will use the @EmptyCase@ language extension. - -- If 'False', derived instances will simply use 'seq' instead. - -- (This has no effect on GHCs before 7.8, since @EmptyCase@ is only - -- available in 7.8 or later.) - } deriving (Eq, Ord, Read, Show) - --- | Conservative 'Options' that doesn't attempt to use @EmptyCase@ (to --- prevent users from having to enable that extension at use sites.) -defaultOptions :: Options -defaultOptions = Options { emptyCaseBehavior = False } - -{- $derive - -'deriveBifunctor', 'deriveBifoldable', and 'deriveBitraversable' automatically -generate their respective class instances for a given data type, newtype, or data -family instance that has at least two type variable. Examples: - -@ -{-# LANGUAGE TemplateHaskell #-} -import Data.Bifunctor.TH - -data Pair a b = Pair a b -$('deriveBifunctor' ''Pair) -- instance Bifunctor Pair where ... - -data WrapLeftPair f g a b = WrapLeftPair (f a) (g a b) -$('deriveBifoldable' ''WrapLeftPair) --- instance (Foldable f, Bifoldable g) => Bifoldable (WrapLeftPair f g) where ... -@ - -If you are using @template-haskell-2.7.0.0@ or later (i.e., GHC 7.4 or later), -the @derive@ functions can be used data family instances (which requires the -@-XTypeFamilies@ extension). To do so, pass the name of a data or newtype instance -constructor (NOT a data family name!) to a @derive@ function. Note that the -generated code may require the @-XFlexibleInstances@ extension. Example: - -@ -{-# LANGUAGE FlexibleInstances, TemplateHaskell, TypeFamilies #-} -import Data.Bifunctor.TH - -class AssocClass a b c where - data AssocData a b c -instance AssocClass Int b c where - data AssocData Int b c = AssocDataInt1 Int | AssocDataInt2 b c -$('deriveBitraversable' 'AssocDataInt1) -- instance Bitraversable (AssocData Int) where ... --- Alternatively, one could use $(deriveBitraversable 'AssocDataInt2) -@ - -Note that there are some limitations: - -* The 'Name' argument to a @derive@ function must not be a type synonym. - -* With a @derive@ function, the last two type variables must both be of kind @*@. - Other type variables of kind @* -> *@ are assumed to require a 'Functor', - 'Foldable', or 'Traversable' constraint (depending on which @derive@ function is - used), and other type variables of kind @* -> * -> *@ are assumed to require an - 'Bifunctor', 'Bifoldable', or 'Bitraversable' constraint. If your data type - doesn't meet these assumptions, use a @make@ function. - -* If using the @-XDatatypeContexts@, @-XExistentialQuantification@, or @-XGADTs@ - extensions, a constraint cannot mention either of the last two type variables. For - example, @data Illegal2 a b where I2 :: Ord a => a -> b -> Illegal2 a b@ cannot - have a derived 'Bifunctor' instance. - -* If either of the last two type variables is used within a constructor argument's - type, it must only be used in the last two type arguments. For example, - @data Legal a b = Legal (Int, Int, a, b)@ can have a derived 'Bifunctor' instance, - but @data Illegal a b = Illegal (a, b, a, b)@ cannot. - -* Data family instances must be able to eta-reduce the last two type variables. In other - words, if you have a instance of the form: - - @ - data family Family a1 ... an t1 t2 - data instance Family e1 ... e2 v1 v2 = ... - @ - - Then the following conditions must hold: - - 1. @v1@ and @v2@ must be distinct type variables. - 2. Neither @v1@ not @v2@ must be mentioned in any of @e1@, ..., @e2@. - --} - -{- $make - -There may be scenarios in which you want to, say, 'bimap' over an arbitrary data type -or data family instance without having to make the type an instance of 'Bifunctor'. For -these cases, this module provides several functions (all prefixed with @make@-) that -splice the appropriate lambda expression into your source code. - -This is particularly useful for creating instances for sophisticated data types. For -example, 'deriveBifunctor' cannot infer the correct type context for -@newtype HigherKinded f a b c = HigherKinded (f a b c)@, since @f@ is of kind -@* -> * -> * -> *@. However, it is still possible to create a 'Bifunctor' instance for -@HigherKinded@ without too much trouble using 'makeBimap': - -@ -{-# LANGUAGE FlexibleContexts, TemplateHaskell #-} -import Data.Bifunctor -import Data.Bifunctor.TH - -newtype HigherKinded f a b c = HigherKinded (f a b c) - -instance Bifunctor (f a) => Bifunctor (HigherKinded f a) where - bimap = $(makeBimap ''HigherKinded) -@ - --} - --- | Generates a 'Bifunctor' instance declaration for the given data type or data --- family instance. -deriveBifunctor :: Name -> Q [Dec] -deriveBifunctor = deriveBifunctorOptions defaultOptions - --- | Like 'deriveBifunctor', but takes an 'Options' argument. -deriveBifunctorOptions :: Options -> Name -> Q [Dec] -deriveBifunctorOptions = deriveBiClass Bifunctor - --- | Generates a lambda expression which behaves like 'bimap' (without requiring a --- 'Bifunctor' instance). -makeBimap :: Name -> Q Exp -makeBimap = makeBimapOptions defaultOptions - --- | Like 'makeBimap', but takes an 'Options' argument. -makeBimapOptions :: Options -> Name -> Q Exp -makeBimapOptions = makeBiFun Bimap - --- | Generates a 'Bifoldable' instance declaration for the given data type or data --- family instance. -deriveBifoldable :: Name -> Q [Dec] -deriveBifoldable = deriveBifoldableOptions defaultOptions - --- | Like 'deriveBifoldable', but takes an 'Options' argument. -deriveBifoldableOptions :: Options -> Name -> Q [Dec] -deriveBifoldableOptions = deriveBiClass Bifoldable - ---- | Generates a lambda expression which behaves like 'bifold' (without requiring a --- 'Bifoldable' instance). -makeBifold :: Name -> Q Exp -makeBifold = makeBifoldOptions defaultOptions - --- | Like 'makeBifold', but takes an 'Options' argument. -makeBifoldOptions :: Options -> Name -> Q Exp -makeBifoldOptions opts name = appsE [ makeBifoldMapOptions opts name - , varE idValName - , varE idValName - ] - --- | Generates a lambda expression which behaves like 'bifoldMap' (without requiring --- a 'Bifoldable' instance). -makeBifoldMap :: Name -> Q Exp -makeBifoldMap = makeBifoldMapOptions defaultOptions - --- | Like 'makeBifoldMap', but takes an 'Options' argument. -makeBifoldMapOptions :: Options -> Name -> Q Exp -makeBifoldMapOptions = makeBiFun BifoldMap - --- | Generates a lambda expression which behaves like 'bifoldr' (without requiring a --- 'Bifoldable' instance). -makeBifoldr :: Name -> Q Exp -makeBifoldr = makeBifoldrOptions defaultOptions - --- | Like 'makeBifoldr', but takes an 'Options' argument. -makeBifoldrOptions :: Options -> Name -> Q Exp -makeBifoldrOptions = makeBiFun Bifoldr - --- | Generates a lambda expression which behaves like 'bifoldl' (without requiring a --- 'Bifoldable' instance). -makeBifoldl :: Name -> Q Exp -makeBifoldl = makeBifoldlOptions defaultOptions - --- | Like 'makeBifoldl', but takes an 'Options' argument. -makeBifoldlOptions :: Options -> Name -> Q Exp -makeBifoldlOptions opts name = do - f <- newName "f" - g <- newName "g" - z <- newName "z" - t <- newName "t" - lamE [varP f, varP g, varP z, varP t] $ - appsE [ varE appEndoValName - , appsE [ varE getDualValName - , appsE [ makeBifoldMapOptions opts name - , foldFun f - , foldFun g - , varE t] - ] - , varE z - ] - where - foldFun :: Name -> Q Exp - foldFun n = infixApp (conE dualDataName) - (varE composeValName) - (infixApp (conE endoDataName) - (varE composeValName) - (varE flipValName `appE` varE n) - ) - --- | Generates a 'Bitraversable' instance declaration for the given data type or data --- family instance. -deriveBitraversable :: Name -> Q [Dec] -deriveBitraversable = deriveBitraversableOptions defaultOptions - --- | Like 'deriveBitraversable', but takes an 'Options' argument. -deriveBitraversableOptions :: Options -> Name -> Q [Dec] -deriveBitraversableOptions = deriveBiClass Bitraversable - --- | Generates a lambda expression which behaves like 'bitraverse' (without --- requiring a 'Bitraversable' instance). -makeBitraverse :: Name -> Q Exp -makeBitraverse = makeBitraverseOptions defaultOptions - --- | Like 'makeBitraverse', but takes an 'Options' argument. -makeBitraverseOptions :: Options -> Name -> Q Exp -makeBitraverseOptions = makeBiFun Bitraverse - --- | Generates a lambda expression which behaves like 'bisequenceA' (without --- requiring a 'Bitraversable' instance). -makeBisequenceA :: Name -> Q Exp -makeBisequenceA = makeBisequenceAOptions defaultOptions - --- | Like 'makeBitraverseA', but takes an 'Options' argument. -makeBisequenceAOptions :: Options -> Name -> Q Exp -makeBisequenceAOptions opts name = appsE [ makeBitraverseOptions opts name - , varE idValName - , varE idValName - ] - --- | Generates a lambda expression which behaves like 'bimapM' (without --- requiring a 'Bitraversable' instance). -makeBimapM :: Name -> Q Exp -makeBimapM = makeBimapMOptions defaultOptions - --- | Like 'makeBimapM', but takes an 'Options' argument. -makeBimapMOptions :: Options -> Name -> Q Exp -makeBimapMOptions opts name = do - f <- newName "f" - g <- newName "g" - lamE [varP f, varP g] . infixApp (varE unwrapMonadValName) (varE composeValName) $ - appsE [ makeBitraverseOptions opts name - , wrapMonadExp f - , wrapMonadExp g - ] - where - wrapMonadExp :: Name -> Q Exp - wrapMonadExp n = infixApp (conE wrapMonadDataName) (varE composeValName) (varE n) - --- | Generates a lambda expression which behaves like 'bisequence' (without --- requiring a 'Bitraversable' instance). -makeBisequence :: Name -> Q Exp -makeBisequence = makeBisequenceOptions defaultOptions - --- | Like 'makeBisequence', but takes an 'Options' argument. -makeBisequenceOptions :: Options -> Name -> Q Exp -makeBisequenceOptions opts name = appsE [ makeBimapMOptions opts name - , varE idValName - , varE idValName - ] - -------------------------------------------------------------------------------- --- Code generation -------------------------------------------------------------------------------- - --- | Derive a class instance declaration (depending on the BiClass argument's value). -deriveBiClass :: BiClass -> Options -> Name -> Q [Dec] -deriveBiClass biClass opts name = do - info <- reifyDatatype name - case info of - DatatypeInfo { datatypeContext = ctxt - , datatypeName = parentName - , datatypeInstTypes = instTys - , datatypeVariant = variant - , datatypeCons = cons - } -> do - (instanceCxt, instanceType) - <- buildTypeInstance biClass parentName ctxt instTys variant - (:[]) `fmap` instanceD (return instanceCxt) - (return instanceType) - (biFunDecs biClass opts parentName instTys cons) - --- | Generates a declaration defining the primary function(s) corresponding to a --- particular class (bimap for Bifunctor, bifoldr and bifoldMap for Bifoldable, and --- bitraverse for Bitraversable). --- --- For why both bifoldr and bifoldMap are derived for Bifoldable, see Trac #7436. -biFunDecs :: BiClass -> Options -> Name -> [Type] -> [ConstructorInfo] -> [Q Dec] -biFunDecs biClass opts parentName instTys cons = - map makeFunD $ biClassToFuns biClass - where - makeFunD :: BiFun -> Q Dec - makeFunD biFun = - funD (biFunName biFun) - [ clause [] - (normalB $ makeBiFunForCons biFun opts parentName instTys cons) - [] - ] - --- | Generates a lambda expression which behaves like the BiFun argument. -makeBiFun :: BiFun -> Options -> Name -> Q Exp -makeBiFun biFun opts name = do - info <- reifyDatatype name - case info of - DatatypeInfo { datatypeContext = ctxt - , datatypeName = parentName - , datatypeInstTypes = instTys - , datatypeVariant = variant - , datatypeCons = cons - } -> - -- We force buildTypeInstance here since it performs some checks for whether - -- or not the provided datatype can actually have bimap/bifoldr/bitraverse/etc. - -- implemented for it, and produces errors if it can't. - buildTypeInstance (biFunToClass biFun) parentName ctxt instTys variant - >> makeBiFunForCons biFun opts parentName instTys cons - --- | Generates a lambda expression for the given constructors. --- All constructors must be from the same type. -makeBiFunForCons :: BiFun -> Options -> Name -> [Type] -> [ConstructorInfo] -> Q Exp -makeBiFunForCons biFun opts _parentName instTys cons = do - map1 <- newName "f" - map2 <- newName "g" - z <- newName "z" -- Only used for deriving bifoldr - value <- newName "value" - let argNames = catMaybes [ Just map1 - , Just map2 - , guard (biFun == Bifoldr) >> Just z - , Just value - ] - lastTyVars = map varTToName $ drop (length instTys - 2) instTys - tvMap = Map.fromList $ zip lastTyVars [map1, map2] - lamE (map varP argNames) - . appsE - $ [ varE $ biFunConstName biFun - , makeFun z value tvMap - ] ++ map varE argNames - where - makeFun :: Name -> Name -> TyVarMap -> Q Exp - makeFun z value tvMap = do -#if MIN_VERSION_template_haskell(2,9,0) - roles <- reifyRoles _parentName -#endif - case () of - _ - -#if MIN_VERSION_template_haskell(2,9,0) - | Just (rs, PhantomR) <- unsnoc roles - , Just (_, PhantomR) <- unsnoc rs - -> biFunPhantom z value -#endif - - | null cons && emptyCaseBehavior opts && ghc7'8OrLater - -> biFunEmptyCase biFun z value - - | null cons - -> biFunNoCons biFun z value - - | otherwise - -> caseE (varE value) - (map (makeBiFunForCon biFun z tvMap) cons) - - ghc7'8OrLater :: Bool -#if __GLASGOW_HASKELL__ >= 708 - ghc7'8OrLater = True -#else - ghc7'8OrLater = False -#endif - -#if MIN_VERSION_template_haskell(2,9,0) - biFunPhantom :: Name -> Name -> Q Exp - biFunPhantom z value = - biFunTrivial coerce - (varE pureValName `appE` coerce) - biFun z - where - coerce :: Q Exp - coerce = varE coerceValName `appE` varE value -#endif - --- | Generates a match for a single constructor. -makeBiFunForCon :: BiFun -> Name -> TyVarMap -> ConstructorInfo -> Q Match -makeBiFunForCon biFun z tvMap - con@(ConstructorInfo { constructorName = conName - , constructorContext = ctxt }) = do - when ((any (`predMentionsName` Map.keys tvMap) ctxt - || Map.size tvMap < 2) - && not (allowExQuant (biFunToClass biFun))) $ - existentialContextError conName - case biFun of - Bimap -> makeBimapMatch tvMap con - Bifoldr -> makeBifoldrMatch z tvMap con - BifoldMap -> makeBifoldMapMatch tvMap con - Bitraverse -> makeBitraverseMatch tvMap con - --- | Generates a match whose right-hand side implements @bimap@. -makeBimapMatch :: TyVarMap -> ConstructorInfo -> Q Match -makeBimapMatch tvMap con@(ConstructorInfo{constructorName = conName}) = do - parts <- foldDataConArgs tvMap ft_bimap con - match_for_con conName parts - where - ft_bimap :: FFoldType (Exp -> Q Exp) - ft_bimap = FT { ft_triv = return - , ft_var = \v x -> return $ VarE (tvMap Map.! v) `AppE` x - , ft_fun = \g h x -> mkSimpleLam $ \b -> do - gg <- g b - h $ x `AppE` gg - , ft_tup = mkSimpleTupleCase match_for_con - , ft_ty_app = \argGs x -> do - let inspect :: (Type, Exp -> Q Exp) -> Q Exp - inspect (argTy, g) - -- If the argument type is a bare occurrence of one - -- of the data type's last type variables, then we - -- can generate more efficient code. - -- This was inspired by GHC#17880. - | Just argVar <- varTToName_maybe argTy - , Just f <- Map.lookup argVar tvMap - = return $ VarE f - | otherwise - = mkSimpleLam g - appsE $ varE (fmapArity (length argGs)) - : map inspect argGs - ++ [return x] - , ft_forall = \_ g x -> g x - , ft_bad_app = \_ -> outOfPlaceTyVarError conName - , ft_co_var = \_ _ -> contravarianceError conName - } - - -- Con a1 a2 ... -> Con (f1 a1) (f2 a2) ... - match_for_con :: Name -> [Exp -> Q Exp] -> Q Match - match_for_con = mkSimpleConMatch $ \conName' xs -> - appsE (conE conName':xs) -- Con x1 x2 .. - --- | Generates a match whose right-hand side implements @bifoldr@. -makeBifoldrMatch :: Name -> TyVarMap -> ConstructorInfo -> Q Match -makeBifoldrMatch z tvMap con@(ConstructorInfo{constructorName = conName}) = do - parts <- foldDataConArgs tvMap ft_bifoldr con - parts' <- sequence parts - match_for_con (VarE z) conName parts' - where - -- The Bool is True if the type mentions of the last two type parameters, - -- False otherwise. Later, match_for_con uses mkSimpleConMatch2 to filter - -- out expressions that do not mention the last parameters by checking for - -- False. - ft_bifoldr :: FFoldType (Q (Bool, Exp)) - ft_bifoldr = FT { -- See Note [ft_triv for Bifoldable and Bitraversable] - ft_triv = do lam <- mkSimpleLam2 $ \_ z' -> return z' - return (False, lam) - , ft_var = \v -> return (True, VarE $ tvMap Map.! v) - , ft_tup = \t gs -> do - gg <- sequence gs - lam <- mkSimpleLam2 $ \x z' -> - mkSimpleTupleCase (match_for_con z') t gg x - return (True, lam) - , ft_ty_app = \gs -> do - lam <- mkSimpleLam2 $ \x z' -> - appsE $ varE (foldrArity (length gs)) - : map (\(_, hs) -> fmap snd hs) gs - ++ map return [z', x] - return (True, lam) - , ft_forall = \_ g -> g - , ft_co_var = \_ -> contravarianceError conName - , ft_fun = \_ _ -> noFunctionsError conName - , ft_bad_app = outOfPlaceTyVarError conName - } - - match_for_con :: Exp -> Name -> [(Bool, Exp)] -> Q Match - match_for_con zExp = mkSimpleConMatch2 $ \_ xs -> return $ mkBifoldr xs - where - -- g1 v1 (g2 v2 (.. z)) - mkBifoldr :: [Exp] -> Exp - mkBifoldr = foldr AppE zExp - --- | Generates a match whose right-hand side implements @bifoldMap@. -makeBifoldMapMatch :: TyVarMap -> ConstructorInfo -> Q Match -makeBifoldMapMatch tvMap con@(ConstructorInfo{constructorName = conName}) = do - parts <- foldDataConArgs tvMap ft_bifoldMap con - parts' <- sequence parts - match_for_con conName parts' - where - -- The Bool is True if the type mentions of the last two type parameters, - -- False otherwise. Later, match_for_con uses mkSimpleConMatch2 to filter - -- out expressions that do not mention the last parameters by checking for - -- False. - ft_bifoldMap :: FFoldType (Q (Bool, Exp)) - ft_bifoldMap = FT { -- See Note [ft_triv for Bifoldable and Bitraversable] - ft_triv = do lam <- mkSimpleLam $ \_ -> return $ VarE memptyValName - return (False, lam) - , ft_var = \v -> return (True, VarE $ tvMap Map.! v) - , ft_tup = \t gs -> do - gg <- sequence gs - lam <- mkSimpleLam $ mkSimpleTupleCase match_for_con t gg - return (True, lam) - , ft_ty_app = \gs -> do - e <- appsE $ varE (foldMapArity (length gs)) - : map (\(_, hs) -> fmap snd hs) gs - return (True, e) - , ft_forall = \_ g -> g - , ft_co_var = \_ -> contravarianceError conName - , ft_fun = \_ _ -> noFunctionsError conName - , ft_bad_app = outOfPlaceTyVarError conName - } - - match_for_con :: Name -> [(Bool, Exp)] -> Q Match - match_for_con = mkSimpleConMatch2 $ \_ xs -> return $ mkBifoldMap xs - where - -- mappend v1 (mappend v2 ..) - mkBifoldMap :: [Exp] -> Exp - mkBifoldMap [] = VarE memptyValName - mkBifoldMap es = foldr1 (AppE . AppE (VarE mappendValName)) es - --- | Generates a match whose right-hand side implements @bitraverse@. -makeBitraverseMatch :: TyVarMap -> ConstructorInfo -> Q Match -makeBitraverseMatch tvMap con@(ConstructorInfo{constructorName = conName}) = do - parts <- foldDataConArgs tvMap ft_bitrav con - parts' <- sequence parts - match_for_con conName parts' - where - -- The Bool is True if the type mentions of the last two type parameters, - -- False otherwise. Later, match_for_con uses mkSimpleConMatch2 to filter - -- out expressions that do not mention the last parameters by checking for - -- False. - ft_bitrav :: FFoldType (Q (Bool, Exp)) - ft_bitrav = FT { -- See Note [ft_triv for Bifoldable and Bitraversable] - ft_triv = return (False, VarE pureValName) - , ft_var = \v -> return (True, VarE $ tvMap Map.! v) - , ft_tup = \t gs -> do - gg <- sequence gs - lam <- mkSimpleLam $ mkSimpleTupleCase match_for_con t gg - return (True, lam) - , ft_ty_app = \gs -> do - e <- appsE $ varE (traverseArity (length gs)) - : map (\(_, hs) -> fmap snd hs) gs - return (True, e) - , ft_forall = \_ g -> g - , ft_co_var = \_ -> contravarianceError conName - , ft_fun = \_ _ -> noFunctionsError conName - , ft_bad_app = outOfPlaceTyVarError conName - } - - -- Con a1 a2 ... -> liftA2 (\b1 b2 ... -> Con b1 b2 ...) (g1 a1) - -- (g2 a2) <*> ... - match_for_con :: Name -> [(Bool, Exp)] -> Q Match - match_for_con = mkSimpleConMatch2 $ \conExp xs -> return $ mkApCon conExp xs - where - -- liftA2 (\b1 b2 ... -> Con b1 b2 ...) x1 x2 <*> .. - mkApCon :: Exp -> [Exp] -> Exp - mkApCon conExp [] = VarE pureValName `AppE` conExp - mkApCon conExp [e] = VarE fmapValName `AppE` conExp `AppE` e - mkApCon conExp (e1:e2:es) = List.foldl' appAp - (VarE liftA2ValName `AppE` conExp `AppE` e1 `AppE` e2) es - where appAp se1 se2 = InfixE (Just se1) (VarE apValName) (Just se2) - -------------------------------------------------------------------------------- --- Template Haskell reifying and AST manipulation -------------------------------------------------------------------------------- - --- For the given Types, generate an instance context and head. Coming up with --- the instance type isn't as simple as dropping the last types, as you need to --- be wary of kinds being instantiated with *. --- See Note [Type inference in derived instances] -buildTypeInstance :: BiClass - -- ^ Bifunctor, Bifoldable, or Bitraversable - -> Name - -- ^ The type constructor or data family name - -> Cxt - -- ^ The datatype context - -> [Type] - -- ^ The types to instantiate the instance with - -> DatatypeVariant - -- ^ Are we dealing with a data family instance or not - -> Q (Cxt, Type) -buildTypeInstance biClass tyConName dataCxt instTysOrig variant = do - -- Make sure to expand through type/kind synonyms! Otherwise, the - -- eta-reduction check might get tripped up over type variables in a - -- synonym that are actually dropped. - -- (See GHC Trac #11416 for a scenario where this actually happened.) - varTysExp <- mapM resolveTypeSynonyms instTysOrig - - let remainingLength :: Int - remainingLength = length instTysOrig - 2 - - droppedTysExp :: [Type] - droppedTysExp = drop remainingLength varTysExp - - droppedStarKindStati :: [StarKindStatus] - droppedStarKindStati = map canRealizeKindStar droppedTysExp - - -- Check there are enough types to drop and that all of them are either of - -- kind * or kind k (for some kind variable k). If not, throw an error. - when (remainingLength < 0 || any (== NotKindStar) droppedStarKindStati) $ - derivingKindError biClass tyConName - - let droppedKindVarNames :: [Name] - droppedKindVarNames = catKindVarNames droppedStarKindStati - - -- Substitute kind * for any dropped kind variables - varTysExpSubst :: [Type] - varTysExpSubst = map (substNamesWithKindStar droppedKindVarNames) varTysExp - - remainingTysExpSubst, droppedTysExpSubst :: [Type] - (remainingTysExpSubst, droppedTysExpSubst) = - splitAt remainingLength varTysExpSubst - - -- All of the type variables mentioned in the dropped types - -- (post-synonym expansion) - droppedTyVarNames :: [Name] - droppedTyVarNames = freeVariables droppedTysExpSubst - - -- If any of the dropped types were polykinded, ensure that they are of kind * - -- after substituting * for the dropped kind variables. If not, throw an error. - unless (all hasKindStar droppedTysExpSubst) $ - derivingKindError biClass tyConName - - let preds :: [Maybe Pred] - kvNames :: [[Name]] - kvNames' :: [Name] - -- Derive instance constraints (and any kind variables which are specialized - -- to * in those constraints) - (preds, kvNames) = unzip $ map (deriveConstraint biClass) remainingTysExpSubst - kvNames' = concat kvNames - - -- Substitute the kind variables specialized in the constraints with * - remainingTysExpSubst' :: [Type] - remainingTysExpSubst' = - map (substNamesWithKindStar kvNames') remainingTysExpSubst - - -- We now substitute all of the specialized-to-* kind variable names with - -- *, but in the original types, not the synonym-expanded types. The reason - -- we do this is a superficial one: we want the derived instance to resemble - -- the datatype written in source code as closely as possible. For example, - -- for the following data family instance: - -- - -- data family Fam a - -- newtype instance Fam String = Fam String - -- - -- We'd want to generate the instance: - -- - -- instance C (Fam String) - -- - -- Not: - -- - -- instance C (Fam [Char]) - remainingTysOrigSubst :: [Type] - remainingTysOrigSubst = - map (substNamesWithKindStar (List.union droppedKindVarNames kvNames')) - $ take remainingLength instTysOrig - - isDataFamily :: Bool - isDataFamily = case variant of - Datatype -> False - Newtype -> False - DataInstance -> True - NewtypeInstance -> True - - remainingTysOrigSubst' :: [Type] - -- See Note [Kind signatures in derived instances] for an explanation - -- of the isDataFamily check. - remainingTysOrigSubst' = - if isDataFamily - then remainingTysOrigSubst - else map unSigT remainingTysOrigSubst - - instanceCxt :: Cxt - instanceCxt = catMaybes preds - - instanceType :: Type - instanceType = AppT (ConT $ biClassName biClass) - $ applyTyCon tyConName remainingTysOrigSubst' - - -- If the datatype context mentions any of the dropped type variables, - -- we can't derive an instance, so throw an error. - when (any (`predMentionsName` droppedTyVarNames) dataCxt) $ - datatypeContextError tyConName instanceType - -- Also ensure the dropped types can be safely eta-reduced. Otherwise, - -- throw an error. - unless (canEtaReduce remainingTysExpSubst' droppedTysExpSubst) $ - etaReductionError instanceType - return (instanceCxt, instanceType) - --- | Attempt to derive a constraint on a Type. If successful, return --- Just the constraint and any kind variable names constrained to *. --- Otherwise, return Nothing and the empty list. --- --- See Note [Type inference in derived instances] for the heuristics used to --- come up with constraints. -deriveConstraint :: BiClass -> Type -> (Maybe Pred, [Name]) -deriveConstraint biClass t - | not (isTyVar t) = (Nothing, []) - | otherwise = case hasKindVarChain 1 t of - Just ns -> ((`applyClass` tName) `fmap` biClassConstraint biClass 1, ns) - _ -> case hasKindVarChain 2 t of - Just ns -> ((`applyClass` tName) `fmap` biClassConstraint biClass 2, ns) - _ -> (Nothing, []) - where - tName :: Name - tName = varTToName t - -{- -Note [Kind signatures in derived instances] -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -It is possible to put explicit kind signatures into the derived instances, e.g., - - instance C a => C (Data (f :: * -> *)) where ... - -But it is preferable to avoid this if possible. If we come up with an incorrect -kind signature (which is entirely possible, since our type inferencer is pretty -unsophisticated - see Note [Type inference in derived instances]), then GHC will -flat-out reject the instance, which is quite unfortunate. - -Plain old datatypes have the advantage that you can avoid using any kind signatures -at all in their instances. This is because a datatype declaration uses all type -variables, so the types that we use in a derived instance uniquely determine their -kinds. As long as we plug in the right types, the kind inferencer can do the rest -of the work. For this reason, we use unSigT to remove all kind signatures before -splicing in the instance context and head. - -Data family instances are trickier, since a data family can have two instances that -are distinguished by kind alone, e.g., - - data family Fam (a :: k) - data instance Fam (a :: * -> *) - data instance Fam (a :: *) - -If we dropped the kind signatures for C (Fam a), then GHC will have no way of -knowing which instance we are talking about. To avoid this scenario, we always -include explicit kind signatures in data family instances. There is a chance that -the inferred kind signatures will be incorrect, but if so, we can always fall back -on the make- functions. - -Note [Type inference in derived instances] -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Type inference is can be tricky to get right, and we want to avoid recreating the -entirety of GHC's type inferencer in Template Haskell. For this reason, we will -probably never come up with derived instance contexts that are as accurate as -GHC's. But that doesn't mean we can't do anything! There are a couple of simple -things we can do to make instance contexts that work for 80% of use cases: - -1. If one of the last type parameters is polykinded, then its kind will be - specialized to * in the derived instance. We note what kind variable the type - parameter had and substitute it with * in the other types as well. For example, - imagine you had - - data Data (a :: k) (b :: k) (c :: k) - - Then you'd want to derived instance to be: - - instance C (Data (a :: *)) - - Not: - - instance C (Data (a :: k)) - -2. We naïvely come up with instance constraints using the following criteria: - - (i) If there's a type parameter n of kind k1 -> k2 (where k1/k2 are * or kind - variables), then generate a Functor n constraint, and if k1/k2 are kind - variables, then substitute k1/k2 with * elsewhere in the types. We must - consider the case where they are kind variables because you might have a - scenario like this: - - newtype Compose (f :: k3 -> *) (g :: k1 -> k2 -> k3) (a :: k1) (b :: k2) - = Compose (f (g a b)) - - Which would have a derived Bifunctor instance of: - - instance (Functor f, Bifunctor g) => Bifunctor (Compose f g) where ... - (ii) If there's a type parameter n of kind k1 -> k2 -> k3 (where k1/k2/k3 are - * or kind variables), then generate a Bifunctor n constraint and perform - kind substitution as in the other case. --} - -{- -Note [Matching functions with GADT type variables] -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -When deriving Bifoldable, there is a tricky corner case to consider: - - data Both a b where - BothCon :: x -> x -> Both x x - -Which fold functions should be applied to which arguments of BothCon? We have a -choice, since both the function of type (a -> m) and of type (b -> m) can be -applied to either argument. In such a scenario, the second fold function takes -precedence over the first fold function, so the derived Bifoldable instance would be: - - instance Bifoldable Both where - bifoldMap _ g (BothCon x1 x2) = g x1 <> g x2 - -This is not an arbitrary choice, as this definition ensures that -bifoldMap id = Foldable.foldMap for a derived Bifoldable instance for Both. --} - -------------------------------------------------------------------------------- --- Error messages -------------------------------------------------------------------------------- - --- | Either the given data type doesn't have enough type variables, or one of --- the type variables to be eta-reduced cannot realize kind *. -derivingKindError :: BiClass -> Name -> Q a -derivingKindError biClass tyConName = fail - . showString "Cannot derive well-kinded instance of form ‘" - . showString className - . showChar ' ' - . showParen True - ( showString (nameBase tyConName) - . showString " ..." - ) - . showString "‘\n\tClass " - . showString className - . showString " expects an argument of kind * -> * -> *" - $ "" - where - className :: String - className = nameBase $ biClassName biClass - --- | One of the last two type variables appeard in a contravariant position --- when deriving Bifoldable or Bitraversable. -contravarianceError :: Name -> Q a -contravarianceError conName = fail - . showString "Constructor ‘" - . showString (nameBase conName) - . showString "‘ must not use the last type variable(s) in a function argument" - $ "" - --- | A constructor has a function argument in a derived Bifoldable or Bitraversable --- instance. -noFunctionsError :: Name -> Q a -noFunctionsError conName = fail - . showString "Constructor ‘" - . showString (nameBase conName) - . showString "‘ must not contain function types" - $ "" - --- | The data type has a DatatypeContext which mentions one of the eta-reduced --- type variables. -datatypeContextError :: Name -> Type -> Q a -datatypeContextError dataName instanceType = fail - . showString "Can't make a derived instance of ‘" - . showString (pprint instanceType) - . showString "‘:\n\tData type ‘" - . showString (nameBase dataName) - . showString "‘ must not have a class context involving the last type argument(s)" - $ "" - --- | The data type has an existential constraint which mentions one of the --- eta-reduced type variables. -existentialContextError :: Name -> Q a -existentialContextError conName = fail - . showString "Constructor ‘" - . showString (nameBase conName) - . showString "‘ must be truly polymorphic in the last argument(s) of the data type" - $ "" - --- | The data type mentions one of the n eta-reduced type variables in a place other --- than the last nth positions of a data type in a constructor's field. -outOfPlaceTyVarError :: Name -> Q a -outOfPlaceTyVarError conName = fail - . showString "Constructor ‘" - . showString (nameBase conName) - . showString "‘ must only use its last two type variable(s) within" - . showString " the last two argument(s) of a data type" - $ "" - --- | One of the last type variables cannot be eta-reduced (see the canEtaReduce --- function for the criteria it would have to meet). -etaReductionError :: Type -> Q a -etaReductionError instanceType = fail $ - "Cannot eta-reduce to an instance of form \n\tinstance (...) => " - ++ pprint instanceType - -------------------------------------------------------------------------------- --- Class-specific constants -------------------------------------------------------------------------------- - --- | A representation of which class is being derived. -data BiClass = Bifunctor | Bifoldable | Bitraversable - --- | A representation of which function is being generated. -data BiFun = Bimap | Bifoldr | BifoldMap | Bitraverse - deriving Eq - -biFunConstName :: BiFun -> Name -biFunConstName Bimap = bimapConstValName -biFunConstName Bifoldr = bifoldrConstValName -biFunConstName BifoldMap = bifoldMapConstValName -biFunConstName Bitraverse = bitraverseConstValName - -biClassName :: BiClass -> Name -biClassName Bifunctor = bifunctorTypeName -biClassName Bifoldable = bifoldableTypeName -biClassName Bitraversable = bitraversableTypeName - -biFunName :: BiFun -> Name -biFunName Bimap = bimapValName -biFunName Bifoldr = bifoldrValName -biFunName BifoldMap = bifoldMapValName -biFunName Bitraverse = bitraverseValName - -biClassToFuns :: BiClass -> [BiFun] -biClassToFuns Bifunctor = [Bimap] -biClassToFuns Bifoldable = [Bifoldr, BifoldMap] -biClassToFuns Bitraversable = [Bitraverse] - -biFunToClass :: BiFun -> BiClass -biFunToClass Bimap = Bifunctor -biFunToClass Bifoldr = Bifoldable -biFunToClass BifoldMap = Bifoldable -biFunToClass Bitraverse = Bitraversable - -biClassConstraint :: BiClass -> Int -> Maybe Name -biClassConstraint Bifunctor 1 = Just functorTypeName -biClassConstraint Bifoldable 1 = Just foldableTypeName -biClassConstraint Bitraversable 1 = Just traversableTypeName -biClassConstraint biClass 2 = Just $ biClassName biClass -biClassConstraint _ _ = Nothing - -fmapArity :: Int -> Name -fmapArity 1 = fmapValName -fmapArity 2 = bimapValName -fmapArity n = arityErr n - -foldrArity :: Int -> Name -foldrArity 1 = foldrValName -foldrArity 2 = bifoldrValName -foldrArity n = arityErr n - -foldMapArity :: Int -> Name -foldMapArity 1 = foldMapValName -foldMapArity 2 = bifoldMapValName -foldMapArity n = arityErr n - -traverseArity :: Int -> Name -traverseArity 1 = traverseValName -traverseArity 2 = bitraverseValName -traverseArity n = arityErr n - -arityErr :: Int -> a -arityErr n = error $ "Unsupported arity: " ++ show n - -allowExQuant :: BiClass -> Bool -allowExQuant Bifoldable = True -allowExQuant _ = False - -biFunEmptyCase :: BiFun -> Name -> Name -> Q Exp -biFunEmptyCase biFun z value = - biFunTrivial emptyCase - (varE pureValName `appE` emptyCase) - biFun z - where - emptyCase :: Q Exp - emptyCase = caseE (varE value) [] - -biFunNoCons :: BiFun -> Name -> Name -> Q Exp -biFunNoCons biFun z value = - biFunTrivial seqAndError - (varE pureValName `appE` seqAndError) - biFun z - where - seqAndError :: Q Exp - seqAndError = appE (varE seqValName) (varE value) `appE` - appE (varE errorValName) - (stringE $ "Void " ++ nameBase (biFunName biFun)) - -biFunTrivial :: Q Exp -> Q Exp -> BiFun -> Name -> Q Exp -biFunTrivial bimapE bitraverseE biFun z = go biFun - where - go :: BiFun -> Q Exp - go Bimap = bimapE - go Bifoldr = varE z - go BifoldMap = varE memptyValName - go Bitraverse = bitraverseE - -{- -Note [ft_triv for Bifoldable and Bitraversable] -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -When deriving Bifoldable and Bitraversable, we filter out any subexpressions whose -type does not mention one of the last two type parameters. From this, you might -think that we don't need to implement ft_triv for bifoldr, bifoldMap, or -bitraverse at all, but in fact we do need to. Imagine the following data type: - - data T a b = MkT a (T Int b) - -In a derived Bifoldable T instance, you would generate the following bifoldMap -definition: - - bifoldMap f g (MkT a1 a2) = f a1 <> bifoldMap (\_ -> mempty) g arg2 - -You need to fill in bi_triv (\_ -> mempty) as the first argument to the recursive -call to bifoldMap, since that is how the algorithm handles polymorphic recursion. --} - -------------------------------------------------------------------------------- --- Generic traversal for functor-like deriving -------------------------------------------------------------------------------- - --- Much of the code below is cargo-culted from the TcGenFunctor module in GHC. - -data FFoldType a -- Describes how to fold over a Type in a functor like way - = FT { ft_triv :: a - -- ^ Does not contain variables - , ft_var :: Name -> a - -- ^ A bare variable - , ft_co_var :: Name -> a - -- ^ A bare variable, contravariantly - , ft_fun :: a -> a -> a - -- ^ Function type - , ft_tup :: TupleSort -> [a] -> a - -- ^ Tuple type. The [a] is the result of folding over the - -- arguments of the tuple. - , ft_ty_app :: [(Type, a)] -> a - -- ^ Type app, variables only in last argument. The [(Type, a)] - -- represents the last argument types. That is, they form the - -- argument parts of @fun_ty arg_ty_1 ... arg_ty_n@. - , ft_bad_app :: a - -- ^ Type app, variable other than in last arguments - , ft_forall :: [TyVarBndrSpec] -> a -> a - -- ^ Forall type - } - --- Note that in GHC, this function is pure. It must be monadic here since we: --- --- (1) Expand type synonyms --- (2) Detect type family applications --- --- Which require reification in Template Haskell, but are pure in Core. -functorLikeTraverse :: forall a. - TyVarMap -- ^ Variables to look for - -> FFoldType a -- ^ How to fold - -> Type -- ^ Type to process - -> Q a -functorLikeTraverse tvMap (FT { ft_triv = caseTrivial, ft_var = caseVar - , ft_co_var = caseCoVar, ft_fun = caseFun - , ft_tup = caseTuple, ft_ty_app = caseTyApp - , ft_bad_app = caseWrongArg, ft_forall = caseForAll }) - ty - = do ty' <- resolveTypeSynonyms ty - (res, _) <- go False ty' - return res - where - go :: Bool -- Covariant or contravariant context - -> Type - -> Q (a, Bool) -- (result of type a, does type contain var) - go co t@AppT{} - | (ArrowT, [funArg, funRes]) <- unapplyTy t - = do (funArgR, funArgC) <- go (not co) funArg - (funResR, funResC) <- go co funRes - if funArgC || funResC - then return (caseFun funArgR funResR, True) - else trivial - go co t@AppT{} = do - let (f, args) = unapplyTy t - (_, fc) <- go co f - (xrs, xcs) <- fmap unzip $ mapM (go co) args - let numLastArgs, numFirstArgs :: Int - numLastArgs = min 2 $ length args - numFirstArgs = length args - numLastArgs - - tuple :: TupleSort -> Q (a, Bool) - tuple tupSort = return (caseTuple tupSort xrs, True) - - wrongArg :: Q (a, Bool) - wrongArg = return (caseWrongArg, True) - - case () of - _ | not (or xcs) - -> trivial -- Variable does not occur - -- At this point we know that xrs, xcs is not empty, - -- and at least one xr is True - | TupleT len <- f - -> tuple $ Boxed len -#if MIN_VERSION_template_haskell(2,6,0) - | UnboxedTupleT len <- f - -> tuple $ Unboxed len -#endif - | fc || or (take numFirstArgs xcs) - -> wrongArg -- T (..var..) ty_1 ... ty_n - | otherwise -- T (..no var..) ty_1 ... ty_n - -> do itf <- isInTypeFamilyApp tyVarNames f args - if itf -- We can't decompose type families, so - -- error if we encounter one here. - then wrongArg - else return ( caseTyApp $ drop numFirstArgs $ zip args xrs - , True ) - go co (SigT t k) = do - (_, kc) <- go_kind co k - if kc - then return (caseWrongArg, True) - else go co t - go co (VarT v) - | Map.member v tvMap - = return (if co then caseCoVar v else caseVar v, True) - | otherwise - = trivial - go co (ForallT tvbs _ t) = do - (tr, tc) <- go co t - let tvbNames = map tvName tvbs - if not tc || any (`elem` tvbNames) tyVarNames - then trivial - else return (caseForAll tvbs tr, True) - go _ _ = trivial - - go_kind :: Bool - -> Kind - -> Q (a, Bool) -#if MIN_VERSION_template_haskell(2,9,0) - go_kind = go -#else - go_kind _ _ = trivial -#endif - - trivial :: Q (a, Bool) - trivial = return (caseTrivial, False) - - tyVarNames :: [Name] - tyVarNames = Map.keys tvMap - --- Fold over the arguments of a data constructor in a Functor-like way. -foldDataConArgs :: forall a. TyVarMap -> FFoldType a -> ConstructorInfo -> Q [a] -foldDataConArgs tvMap ft con = do - fieldTys <- mapM resolveTypeSynonyms $ constructorFields con - mapM foldArg fieldTys - where - foldArg :: Type -> Q a - foldArg = functorLikeTraverse tvMap ft - --- Make a 'LamE' using a fresh variable. -mkSimpleLam :: (Exp -> Q Exp) -> Q Exp -mkSimpleLam lam = do - -- Use an underscore in front of the variable name, as it's possible for - -- certain Bifoldable instances to generate code like this (see #89): - -- - -- @ - -- bifoldMap (\\_n -> mempty) ... - -- @ - -- - -- Without the underscore, that code would trigger -Wunused-matches warnings. - n <- newName "_n" - body <- lam (VarE n) - return $ LamE [VarP n] body - --- Make a 'LamE' using two fresh variables. -mkSimpleLam2 :: (Exp -> Exp -> Q Exp) -> Q Exp -mkSimpleLam2 lam = do - -- Use an underscore in front of the variable name, as it's possible for - -- certain Bifoldable instances to generate code like this (see #89): - -- - -- @ - -- bifoldr (\\_n1 n2 -> n2) ... - -- @ - -- - -- Without the underscore, that code would trigger -Wunused-matches warnings. - n1 <- newName "_n1" - n2 <- newName "n2" - body <- lam (VarE n1) (VarE n2) - return $ LamE [VarP n1, VarP n2] body - --- "Con a1 a2 a3 -> fold [x1 a1, x2 a2, x3 a3]" --- --- @mkSimpleConMatch fold conName insides@ produces a match clause in --- which the LHS pattern-matches on @extraPats@, followed by a match on the --- constructor @conName@ and its arguments. The RHS folds (with @fold@) over --- @conName@ and its arguments, applying an expression (from @insides@) to each --- of the respective arguments of @conName@. -mkSimpleConMatch :: (Name -> [a] -> Q Exp) - -> Name - -> [Exp -> a] - -> Q Match -mkSimpleConMatch fold conName insides = do - varsNeeded <- newNameList "_arg" $ length insides - let pat = conPCompat conName (map VarP varsNeeded) - rhs <- fold conName (zipWith (\i v -> i $ VarE v) insides varsNeeded) - return $ Match pat (NormalB rhs) [] - --- "Con a1 a2 a3 -> fmap (\b2 -> Con a1 b2 a3) (traverse f a2)" --- --- @mkSimpleConMatch2 fold conName insides@ behaves very similarly to --- 'mkSimpleConMatch', with two key differences: --- --- 1. @insides@ is a @[(Bool, Exp)]@ instead of a @[Exp]@. This is because it --- filters out the expressions corresponding to arguments whose types do not --- mention the last type variable in a derived 'Foldable' or 'Traversable' --- instance (i.e., those elements of @insides@ containing @False@). --- --- 2. @fold@ takes an expression as its first argument instead of a --- constructor name. This is because it uses a specialized --- constructor function expression that only takes as many parameters as --- there are argument types that mention the last type variable. -mkSimpleConMatch2 :: (Exp -> [Exp] -> Q Exp) - -> Name - -> [(Bool, Exp)] - -> Q Match -mkSimpleConMatch2 fold conName insides = do - varsNeeded <- newNameList "_arg" lengthInsides - let pat = conPCompat conName (map VarP varsNeeded) - -- Make sure to zip BEFORE invoking catMaybes. We want the variable - -- indicies in each expression to match up with the argument indices - -- in conExpr (defined below). - exps = catMaybes $ zipWith (\(m, i) v -> if m then Just (i `AppE` VarE v) - else Nothing) - insides varsNeeded - -- An element of argTysTyVarInfo is True if the constructor argument - -- with the same index has a type which mentions the last type - -- variable. - argTysTyVarInfo = map (\(m, _) -> m) insides - (asWithTyVar, asWithoutTyVar) = partitionByList argTysTyVarInfo varsNeeded - - conExpQ - | null asWithTyVar = appsE (conE conName:map varE asWithoutTyVar) - | otherwise = do - bs <- newNameList "b" lengthInsides - let bs' = filterByList argTysTyVarInfo bs - vars = filterByLists argTysTyVarInfo - (map varE bs) (map varE varsNeeded) - lamE (map varP bs') (appsE (conE conName:vars)) - - conExp <- conExpQ - rhs <- fold conExp exps - return $ Match pat (NormalB rhs) [] - where - lengthInsides = length insides - --- Indicates whether a tuple is boxed or unboxed, as well as its number of --- arguments. For instance, (a, b) corresponds to @Boxed 2@, and (# a, b, c #) --- corresponds to @Unboxed 3@. -data TupleSort - = Boxed Int -#if MIN_VERSION_template_haskell(2,6,0) - | Unboxed Int -#endif - --- "case x of (a1,a2,a3) -> fold [x1 a1, x2 a2, x3 a3]" -mkSimpleTupleCase :: (Name -> [a] -> Q Match) - -> TupleSort -> [a] -> Exp -> Q Exp -mkSimpleTupleCase matchForCon tupSort insides x = do - let tupDataName = case tupSort of - Boxed len -> tupleDataName len -#if MIN_VERSION_template_haskell(2,6,0) - Unboxed len -> unboxedTupleDataName len -#endif - m <- matchForCon tupDataName insides - return $ CaseE x [m] - --- Adapt to the type of ConP changing in template-haskell-2.18.0.0. -conPCompat :: Name -> [Pat] -> Pat -conPCompat n pats = ConP n -#if MIN_VERSION_template_haskell(2,18,0) - [] -#endif - pats +{-# LANGUAGE CPP #-} +{-# LANGUAGE BangPatterns #-} +{-# LANGUAGE PatternGuards #-} +{-# LANGUAGE ScopedTypeVariables #-} + +#if __GLASGOW_HASKELL__ >= 704 +{-# LANGUAGE Unsafe #-} +#endif + +#ifndef MIN_VERSION_template_haskell +#define MIN_VERSION_template_haskell(x,y,z) 1 +#endif +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2008-2016 Edward Kmett, (C) 2015-2016 Ryan Scott +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +-- Functions to mechanically derive 'Bifunctor', 'Bifoldable', +-- or 'Bitraversable' instances, or to splice their functions directly into +-- source code. You need to enable the @TemplateHaskell@ language extension +-- in order to use this module. +---------------------------------------------------------------------------- + +module Data.Bifunctor.TH ( + -- * @derive@- functions + -- $derive + -- * @make@- functions + -- $make + -- * 'Bifunctor' + deriveBifunctor + , deriveBifunctorOptions + , makeBimap + , makeBimapOptions + -- * 'Bifoldable' + , deriveBifoldable + , deriveBifoldableOptions + , makeBifold + , makeBifoldOptions + , makeBifoldMap + , makeBifoldMapOptions + , makeBifoldr + , makeBifoldrOptions + , makeBifoldl + , makeBifoldlOptions + -- * 'Bitraversable' + , deriveBitraversable + , deriveBitraversableOptions + , makeBitraverse + , makeBitraverseOptions + , makeBisequenceA + , makeBisequenceAOptions + , makeBimapM + , makeBimapMOptions + , makeBisequence + , makeBisequenceOptions + -- * 'Options' + , Options(..) + , defaultOptions + ) where + +import Control.Monad (guard, unless, when) + +import Data.Bifunctor.TH.Internal +import qualified Data.List as List +import qualified Data.Map as Map ((!), fromList, keys, lookup, member, size) +import Data.Maybe + +import Language.Haskell.TH.Datatype +import Language.Haskell.TH.Datatype.TyVarBndr +import Language.Haskell.TH.Lib +import Language.Haskell.TH.Ppr +import Language.Haskell.TH.Syntax + +------------------------------------------------------------------------------- +-- User-facing API +------------------------------------------------------------------------------- + +-- | Options that further configure how the functions in "Data.Bifunctor.TH" +-- should behave. +newtype Options = Options + { emptyCaseBehavior :: Bool + -- ^ If 'True', derived instances for empty data types (i.e., ones with + -- no data constructors) will use the @EmptyCase@ language extension. + -- If 'False', derived instances will simply use 'seq' instead. + -- (This has no effect on GHCs before 7.8, since @EmptyCase@ is only + -- available in 7.8 or later.) + } deriving (Eq, Ord, Read, Show) + +-- | Conservative 'Options' that doesn't attempt to use @EmptyCase@ (to +-- prevent users from having to enable that extension at use sites.) +defaultOptions :: Options +defaultOptions = Options { emptyCaseBehavior = False } + +{- $derive + +'deriveBifunctor', 'deriveBifoldable', and 'deriveBitraversable' automatically +generate their respective class instances for a given data type, newtype, or data +family instance that has at least two type variable. Examples: + +@ +{-# LANGUAGE TemplateHaskell #-} +import Data.Bifunctor.TH + +data Pair a b = Pair a b +$('deriveBifunctor' ''Pair) -- instance Bifunctor Pair where ... + +data WrapLeftPair f g a b = WrapLeftPair (f a) (g a b) +$('deriveBifoldable' ''WrapLeftPair) +-- instance (Foldable f, Bifoldable g) => Bifoldable (WrapLeftPair f g) where ... +@ + +If you are using @template-haskell-2.7.0.0@ or later (i.e., GHC 7.4 or later), +the @derive@ functions can be used data family instances (which requires the +@-XTypeFamilies@ extension). To do so, pass the name of a data or newtype instance +constructor (NOT a data family name!) to a @derive@ function. Note that the +generated code may require the @-XFlexibleInstances@ extension. Example: + +@ +{-# LANGUAGE FlexibleInstances, TemplateHaskell, TypeFamilies #-} +import Data.Bifunctor.TH + +class AssocClass a b c where + data AssocData a b c +instance AssocClass Int b c where + data AssocData Int b c = AssocDataInt1 Int | AssocDataInt2 b c +$('deriveBitraversable' 'AssocDataInt1) -- instance Bitraversable (AssocData Int) where ... +-- Alternatively, one could use $(deriveBitraversable 'AssocDataInt2) +@ + +Note that there are some limitations: + +* The 'Name' argument to a @derive@ function must not be a type synonym. + +* With a @derive@ function, the last two type variables must both be of kind @*@. + Other type variables of kind @* -> *@ are assumed to require a 'Functor', + 'Foldable', or 'Traversable' constraint (depending on which @derive@ function is + used), and other type variables of kind @* -> * -> *@ are assumed to require an + 'Bifunctor', 'Bifoldable', or 'Bitraversable' constraint. If your data type + doesn't meet these assumptions, use a @make@ function. + +* If using the @-XDatatypeContexts@, @-XExistentialQuantification@, or @-XGADTs@ + extensions, a constraint cannot mention either of the last two type variables. For + example, @data Illegal2 a b where I2 :: Ord a => a -> b -> Illegal2 a b@ cannot + have a derived 'Bifunctor' instance. + +* If either of the last two type variables is used within a constructor argument's + type, it must only be used in the last two type arguments. For example, + @data Legal a b = Legal (Int, Int, a, b)@ can have a derived 'Bifunctor' instance, + but @data Illegal a b = Illegal (a, b, a, b)@ cannot. + +* Data family instances must be able to eta-reduce the last two type variables. In other + words, if you have a instance of the form: + + @ + data family Family a1 ... an t1 t2 + data instance Family e1 ... e2 v1 v2 = ... + @ + + Then the following conditions must hold: + + 1. @v1@ and @v2@ must be distinct type variables. + 2. Neither @v1@ not @v2@ must be mentioned in any of @e1@, ..., @e2@. + +-} + +{- $make + +There may be scenarios in which you want to, say, 'bimap' over an arbitrary data type +or data family instance without having to make the type an instance of 'Bifunctor'. For +these cases, this module provides several functions (all prefixed with @make@-) that +splice the appropriate lambda expression into your source code. + +This is particularly useful for creating instances for sophisticated data types. For +example, 'deriveBifunctor' cannot infer the correct type context for +@newtype HigherKinded f a b c = HigherKinded (f a b c)@, since @f@ is of kind +@* -> * -> * -> *@. However, it is still possible to create a 'Bifunctor' instance for +@HigherKinded@ without too much trouble using 'makeBimap': + +@ +{-# LANGUAGE FlexibleContexts, TemplateHaskell #-} +import Data.Bifunctor +import Data.Bifunctor.TH + +newtype HigherKinded f a b c = HigherKinded (f a b c) + +instance Bifunctor (f a) => Bifunctor (HigherKinded f a) where + bimap = $(makeBimap ''HigherKinded) +@ + +-} + +-- | Generates a 'Bifunctor' instance declaration for the given data type or data +-- family instance. +deriveBifunctor :: Name -> Q [Dec] +deriveBifunctor = deriveBifunctorOptions defaultOptions + +-- | Like 'deriveBifunctor', but takes an 'Options' argument. +deriveBifunctorOptions :: Options -> Name -> Q [Dec] +deriveBifunctorOptions = deriveBiClass Bifunctor + +-- | Generates a lambda expression which behaves like 'bimap' (without requiring a +-- 'Bifunctor' instance). +makeBimap :: Name -> Q Exp +makeBimap = makeBimapOptions defaultOptions + +-- | Like 'makeBimap', but takes an 'Options' argument. +makeBimapOptions :: Options -> Name -> Q Exp +makeBimapOptions = makeBiFun Bimap + +-- | Generates a 'Bifoldable' instance declaration for the given data type or data +-- family instance. +deriveBifoldable :: Name -> Q [Dec] +deriveBifoldable = deriveBifoldableOptions defaultOptions + +-- | Like 'deriveBifoldable', but takes an 'Options' argument. +deriveBifoldableOptions :: Options -> Name -> Q [Dec] +deriveBifoldableOptions = deriveBiClass Bifoldable + +--- | Generates a lambda expression which behaves like 'bifold' (without requiring a +-- 'Bifoldable' instance). +makeBifold :: Name -> Q Exp +makeBifold = makeBifoldOptions defaultOptions + +-- | Like 'makeBifold', but takes an 'Options' argument. +makeBifoldOptions :: Options -> Name -> Q Exp +makeBifoldOptions opts name = appsE [ makeBifoldMapOptions opts name + , varE idValName + , varE idValName + ] + +-- | Generates a lambda expression which behaves like 'bifoldMap' (without requiring +-- a 'Bifoldable' instance). +makeBifoldMap :: Name -> Q Exp +makeBifoldMap = makeBifoldMapOptions defaultOptions + +-- | Like 'makeBifoldMap', but takes an 'Options' argument. +makeBifoldMapOptions :: Options -> Name -> Q Exp +makeBifoldMapOptions = makeBiFun BifoldMap + +-- | Generates a lambda expression which behaves like 'bifoldr' (without requiring a +-- 'Bifoldable' instance). +makeBifoldr :: Name -> Q Exp +makeBifoldr = makeBifoldrOptions defaultOptions + +-- | Like 'makeBifoldr', but takes an 'Options' argument. +makeBifoldrOptions :: Options -> Name -> Q Exp +makeBifoldrOptions = makeBiFun Bifoldr + +-- | Generates a lambda expression which behaves like 'bifoldl' (without requiring a +-- 'Bifoldable' instance). +makeBifoldl :: Name -> Q Exp +makeBifoldl = makeBifoldlOptions defaultOptions + +-- | Like 'makeBifoldl', but takes an 'Options' argument. +makeBifoldlOptions :: Options -> Name -> Q Exp +makeBifoldlOptions opts name = do + f <- newName "f" + g <- newName "g" + z <- newName "z" + t <- newName "t" + lamE [varP f, varP g, varP z, varP t] $ + appsE [ varE appEndoValName + , appsE [ varE getDualValName + , appsE [ makeBifoldMapOptions opts name + , foldFun f + , foldFun g + , varE t] + ] + , varE z + ] + where + foldFun :: Name -> Q Exp + foldFun n = infixApp (conE dualDataName) + (varE composeValName) + (infixApp (conE endoDataName) + (varE composeValName) + (varE flipValName `appE` varE n) + ) + +-- | Generates a 'Bitraversable' instance declaration for the given data type or data +-- family instance. +deriveBitraversable :: Name -> Q [Dec] +deriveBitraversable = deriveBitraversableOptions defaultOptions + +-- | Like 'deriveBitraversable', but takes an 'Options' argument. +deriveBitraversableOptions :: Options -> Name -> Q [Dec] +deriveBitraversableOptions = deriveBiClass Bitraversable + +-- | Generates a lambda expression which behaves like 'bitraverse' (without +-- requiring a 'Bitraversable' instance). +makeBitraverse :: Name -> Q Exp +makeBitraverse = makeBitraverseOptions defaultOptions + +-- | Like 'makeBitraverse', but takes an 'Options' argument. +makeBitraverseOptions :: Options -> Name -> Q Exp +makeBitraverseOptions = makeBiFun Bitraverse + +-- | Generates a lambda expression which behaves like 'bisequenceA' (without +-- requiring a 'Bitraversable' instance). +makeBisequenceA :: Name -> Q Exp +makeBisequenceA = makeBisequenceAOptions defaultOptions + +-- | Like 'makeBitraverseA', but takes an 'Options' argument. +makeBisequenceAOptions :: Options -> Name -> Q Exp +makeBisequenceAOptions opts name = appsE [ makeBitraverseOptions opts name + , varE idValName + , varE idValName + ] + +-- | Generates a lambda expression which behaves like 'bimapM' (without +-- requiring a 'Bitraversable' instance). +makeBimapM :: Name -> Q Exp +makeBimapM = makeBimapMOptions defaultOptions + +-- | Like 'makeBimapM', but takes an 'Options' argument. +makeBimapMOptions :: Options -> Name -> Q Exp +makeBimapMOptions opts name = do + f <- newName "f" + g <- newName "g" + lamE [varP f, varP g] . infixApp (varE unwrapMonadValName) (varE composeValName) $ + appsE [ makeBitraverseOptions opts name + , wrapMonadExp f + , wrapMonadExp g + ] + where + wrapMonadExp :: Name -> Q Exp + wrapMonadExp n = infixApp (conE wrapMonadDataName) (varE composeValName) (varE n) + +-- | Generates a lambda expression which behaves like 'bisequence' (without +-- requiring a 'Bitraversable' instance). +makeBisequence :: Name -> Q Exp +makeBisequence = makeBisequenceOptions defaultOptions + +-- | Like 'makeBisequence', but takes an 'Options' argument. +makeBisequenceOptions :: Options -> Name -> Q Exp +makeBisequenceOptions opts name = appsE [ makeBimapMOptions opts name + , varE idValName + , varE idValName + ] + +------------------------------------------------------------------------------- +-- Code generation +------------------------------------------------------------------------------- + +-- | Derive a class instance declaration (depending on the BiClass argument's value). +deriveBiClass :: BiClass -> Options -> Name -> Q [Dec] +deriveBiClass biClass opts name = do + info <- reifyDatatype name + case info of + DatatypeInfo { datatypeContext = ctxt + , datatypeName = parentName + , datatypeInstTypes = instTys + , datatypeVariant = variant + , datatypeCons = cons + } -> do + (instanceCxt, instanceType) + <- buildTypeInstance biClass parentName ctxt instTys variant + (:[]) `fmap` instanceD (return instanceCxt) + (return instanceType) + (biFunDecs biClass opts parentName instTys cons) + +-- | Generates a declaration defining the primary function(s) corresponding to a +-- particular class (bimap for Bifunctor, bifoldr and bifoldMap for Bifoldable, and +-- bitraverse for Bitraversable). +-- +-- For why both bifoldr and bifoldMap are derived for Bifoldable, see Trac #7436. +biFunDecs :: BiClass -> Options -> Name -> [Type] -> [ConstructorInfo] -> [Q Dec] +biFunDecs biClass opts parentName instTys cons = + map makeFunD $ biClassToFuns biClass + where + makeFunD :: BiFun -> Q Dec + makeFunD biFun = + funD (biFunName biFun) + [ clause [] + (normalB $ makeBiFunForCons biFun opts parentName instTys cons) + [] + ] + +-- | Generates a lambda expression which behaves like the BiFun argument. +makeBiFun :: BiFun -> Options -> Name -> Q Exp +makeBiFun biFun opts name = do + info <- reifyDatatype name + case info of + DatatypeInfo { datatypeContext = ctxt + , datatypeName = parentName + , datatypeInstTypes = instTys + , datatypeVariant = variant + , datatypeCons = cons + } -> + -- We force buildTypeInstance here since it performs some checks for whether + -- or not the provided datatype can actually have bimap/bifoldr/bitraverse/etc. + -- implemented for it, and produces errors if it can't. + buildTypeInstance (biFunToClass biFun) parentName ctxt instTys variant + >> makeBiFunForCons biFun opts parentName instTys cons + +-- | Generates a lambda expression for the given constructors. +-- All constructors must be from the same type. +makeBiFunForCons :: BiFun -> Options -> Name -> [Type] -> [ConstructorInfo] -> Q Exp +makeBiFunForCons biFun opts _parentName instTys cons = do + map1 <- newName "f" + map2 <- newName "g" + z <- newName "z" -- Only used for deriving bifoldr + value <- newName "value" + let argNames = catMaybes [ Just map1 + , Just map2 + , guard (biFun == Bifoldr) >> Just z + , Just value + ] + lastTyVars = map varTToName $ drop (length instTys - 2) instTys + tvMap = Map.fromList $ zip lastTyVars [map1, map2] + lamE (map varP argNames) + . appsE + $ [ varE $ biFunConstName biFun + , makeFun z value tvMap + ] ++ map varE argNames + where + makeFun :: Name -> Name -> TyVarMap -> Q Exp + makeFun z value tvMap = do +#if MIN_VERSION_template_haskell(2,9,0) + roles <- reifyRoles _parentName +#endif + case () of + _ + +#if MIN_VERSION_template_haskell(2,9,0) + | Just (rs, PhantomR) <- unsnoc roles + , Just (_, PhantomR) <- unsnoc rs + -> biFunPhantom z value +#endif + + | null cons && emptyCaseBehavior opts && ghc7'8OrLater + -> biFunEmptyCase biFun z value + + | null cons + -> biFunNoCons biFun z value + + | otherwise + -> caseE (varE value) + (map (makeBiFunForCon biFun z tvMap) cons) + + ghc7'8OrLater :: Bool +#if __GLASGOW_HASKELL__ >= 708 + ghc7'8OrLater = True +#else + ghc7'8OrLater = False +#endif + +#if MIN_VERSION_template_haskell(2,9,0) + biFunPhantom :: Name -> Name -> Q Exp + biFunPhantom z value = + biFunTrivial coerce + (varE pureValName `appE` coerce) + biFun z + where + coerce :: Q Exp + coerce = varE coerceValName `appE` varE value +#endif + +-- | Generates a match for a single constructor. +makeBiFunForCon :: BiFun -> Name -> TyVarMap -> ConstructorInfo -> Q Match +makeBiFunForCon biFun z tvMap + con@(ConstructorInfo { constructorName = conName + , constructorContext = ctxt }) = do + when ((any (`predMentionsName` Map.keys tvMap) ctxt + || Map.size tvMap < 2) + && not (allowExQuant (biFunToClass biFun))) $ + existentialContextError conName + case biFun of + Bimap -> makeBimapMatch tvMap con + Bifoldr -> makeBifoldrMatch z tvMap con + BifoldMap -> makeBifoldMapMatch tvMap con + Bitraverse -> makeBitraverseMatch tvMap con + +-- | Generates a match whose right-hand side implements @bimap@. +makeBimapMatch :: TyVarMap -> ConstructorInfo -> Q Match +makeBimapMatch tvMap con@(ConstructorInfo{constructorName = conName}) = do + parts <- foldDataConArgs tvMap ft_bimap con + match_for_con conName parts + where + ft_bimap :: FFoldType (Exp -> Q Exp) + ft_bimap = FT { ft_triv = return + , ft_var = \v x -> return $ VarE (tvMap Map.! v) `AppE` x + , ft_fun = \g h x -> mkSimpleLam $ \b -> do + gg <- g b + h $ x `AppE` gg + , ft_tup = mkSimpleTupleCase match_for_con + , ft_ty_app = \argGs x -> do + let inspect :: (Type, Exp -> Q Exp) -> Q Exp + inspect (argTy, g) + -- If the argument type is a bare occurrence of one + -- of the data type's last type variables, then we + -- can generate more efficient code. + -- This was inspired by GHC#17880. + | Just argVar <- varTToName_maybe argTy + , Just f <- Map.lookup argVar tvMap + = return $ VarE f + | otherwise + = mkSimpleLam g + appsE $ varE (fmapArity (length argGs)) + : map inspect argGs + ++ [return x] + , ft_forall = \_ g x -> g x + , ft_bad_app = \_ -> outOfPlaceTyVarError conName + , ft_co_var = \_ _ -> contravarianceError conName + } + + -- Con a1 a2 ... -> Con (f1 a1) (f2 a2) ... + match_for_con :: Name -> [Exp -> Q Exp] -> Q Match + match_for_con = mkSimpleConMatch $ \conName' xs -> + appsE (conE conName':xs) -- Con x1 x2 .. + +-- | Generates a match whose right-hand side implements @bifoldr@. +makeBifoldrMatch :: Name -> TyVarMap -> ConstructorInfo -> Q Match +makeBifoldrMatch z tvMap con@(ConstructorInfo{constructorName = conName}) = do + parts <- foldDataConArgs tvMap ft_bifoldr con + parts' <- sequence parts + match_for_con (VarE z) conName parts' + where + -- The Bool is True if the type mentions of the last two type parameters, + -- False otherwise. Later, match_for_con uses mkSimpleConMatch2 to filter + -- out expressions that do not mention the last parameters by checking for + -- False. + ft_bifoldr :: FFoldType (Q (Bool, Exp)) + ft_bifoldr = FT { -- See Note [ft_triv for Bifoldable and Bitraversable] + ft_triv = do lam <- mkSimpleLam2 $ \_ z' -> return z' + return (False, lam) + , ft_var = \v -> return (True, VarE $ tvMap Map.! v) + , ft_tup = \t gs -> do + gg <- sequence gs + lam <- mkSimpleLam2 $ \x z' -> + mkSimpleTupleCase (match_for_con z') t gg x + return (True, lam) + , ft_ty_app = \gs -> do + lam <- mkSimpleLam2 $ \x z' -> + appsE $ varE (foldrArity (length gs)) + : map (\(_, hs) -> fmap snd hs) gs + ++ map return [z', x] + return (True, lam) + , ft_forall = \_ g -> g + , ft_co_var = \_ -> contravarianceError conName + , ft_fun = \_ _ -> noFunctionsError conName + , ft_bad_app = outOfPlaceTyVarError conName + } + + match_for_con :: Exp -> Name -> [(Bool, Exp)] -> Q Match + match_for_con zExp = mkSimpleConMatch2 $ \_ xs -> return $ mkBifoldr xs + where + -- g1 v1 (g2 v2 (.. z)) + mkBifoldr :: [Exp] -> Exp + mkBifoldr = foldr AppE zExp + +-- | Generates a match whose right-hand side implements @bifoldMap@. +makeBifoldMapMatch :: TyVarMap -> ConstructorInfo -> Q Match +makeBifoldMapMatch tvMap con@(ConstructorInfo{constructorName = conName}) = do + parts <- foldDataConArgs tvMap ft_bifoldMap con + parts' <- sequence parts + match_for_con conName parts' + where + -- The Bool is True if the type mentions of the last two type parameters, + -- False otherwise. Later, match_for_con uses mkSimpleConMatch2 to filter + -- out expressions that do not mention the last parameters by checking for + -- False. + ft_bifoldMap :: FFoldType (Q (Bool, Exp)) + ft_bifoldMap = FT { -- See Note [ft_triv for Bifoldable and Bitraversable] + ft_triv = do lam <- mkSimpleLam $ \_ -> return $ VarE memptyValName + return (False, lam) + , ft_var = \v -> return (True, VarE $ tvMap Map.! v) + , ft_tup = \t gs -> do + gg <- sequence gs + lam <- mkSimpleLam $ mkSimpleTupleCase match_for_con t gg + return (True, lam) + , ft_ty_app = \gs -> do + e <- appsE $ varE (foldMapArity (length gs)) + : map (\(_, hs) -> fmap snd hs) gs + return (True, e) + , ft_forall = \_ g -> g + , ft_co_var = \_ -> contravarianceError conName + , ft_fun = \_ _ -> noFunctionsError conName + , ft_bad_app = outOfPlaceTyVarError conName + } + + match_for_con :: Name -> [(Bool, Exp)] -> Q Match + match_for_con = mkSimpleConMatch2 $ \_ xs -> return $ mkBifoldMap xs + where + -- mappend v1 (mappend v2 ..) + mkBifoldMap :: [Exp] -> Exp + mkBifoldMap [] = VarE memptyValName + mkBifoldMap es = foldr1 (AppE . AppE (VarE mappendValName)) es + +-- | Generates a match whose right-hand side implements @bitraverse@. +makeBitraverseMatch :: TyVarMap -> ConstructorInfo -> Q Match +makeBitraverseMatch tvMap con@(ConstructorInfo{constructorName = conName}) = do + parts <- foldDataConArgs tvMap ft_bitrav con + parts' <- sequence parts + match_for_con conName parts' + where + -- The Bool is True if the type mentions of the last two type parameters, + -- False otherwise. Later, match_for_con uses mkSimpleConMatch2 to filter + -- out expressions that do not mention the last parameters by checking for + -- False. + ft_bitrav :: FFoldType (Q (Bool, Exp)) + ft_bitrav = FT { -- See Note [ft_triv for Bifoldable and Bitraversable] + ft_triv = return (False, VarE pureValName) + , ft_var = \v -> return (True, VarE $ tvMap Map.! v) + , ft_tup = \t gs -> do + gg <- sequence gs + lam <- mkSimpleLam $ mkSimpleTupleCase match_for_con t gg + return (True, lam) + , ft_ty_app = \gs -> do + e <- appsE $ varE (traverseArity (length gs)) + : map (\(_, hs) -> fmap snd hs) gs + return (True, e) + , ft_forall = \_ g -> g + , ft_co_var = \_ -> contravarianceError conName + , ft_fun = \_ _ -> noFunctionsError conName + , ft_bad_app = outOfPlaceTyVarError conName + } + + -- Con a1 a2 ... -> liftA2 (\b1 b2 ... -> Con b1 b2 ...) (g1 a1) + -- (g2 a2) <*> ... + match_for_con :: Name -> [(Bool, Exp)] -> Q Match + match_for_con = mkSimpleConMatch2 $ \conExp xs -> return $ mkApCon conExp xs + where + -- liftA2 (\b1 b2 ... -> Con b1 b2 ...) x1 x2 <*> .. + mkApCon :: Exp -> [Exp] -> Exp + mkApCon conExp [] = VarE pureValName `AppE` conExp + mkApCon conExp [e] = VarE fmapValName `AppE` conExp `AppE` e + mkApCon conExp (e1:e2:es) = List.foldl' appAp + (VarE liftA2ValName `AppE` conExp `AppE` e1 `AppE` e2) es + where appAp se1 se2 = InfixE (Just se1) (VarE apValName) (Just se2) + +------------------------------------------------------------------------------- +-- Template Haskell reifying and AST manipulation +------------------------------------------------------------------------------- + +-- For the given Types, generate an instance context and head. Coming up with +-- the instance type isn't as simple as dropping the last types, as you need to +-- be wary of kinds being instantiated with *. +-- See Note [Type inference in derived instances] +buildTypeInstance :: BiClass + -- ^ Bifunctor, Bifoldable, or Bitraversable + -> Name + -- ^ The type constructor or data family name + -> Cxt + -- ^ The datatype context + -> [Type] + -- ^ The types to instantiate the instance with + -> DatatypeVariant + -- ^ Are we dealing with a data family instance or not + -> Q (Cxt, Type) +buildTypeInstance biClass tyConName dataCxt instTysOrig variant = do + -- Make sure to expand through type/kind synonyms! Otherwise, the + -- eta-reduction check might get tripped up over type variables in a + -- synonym that are actually dropped. + -- (See GHC Trac #11416 for a scenario where this actually happened.) + varTysExp <- mapM resolveTypeSynonyms instTysOrig + + let remainingLength :: Int + remainingLength = length instTysOrig - 2 + + droppedTysExp :: [Type] + droppedTysExp = drop remainingLength varTysExp + + droppedStarKindStati :: [StarKindStatus] + droppedStarKindStati = map canRealizeKindStar droppedTysExp + + -- Check there are enough types to drop and that all of them are either of + -- kind * or kind k (for some kind variable k). If not, throw an error. + when (remainingLength < 0 || any (== NotKindStar) droppedStarKindStati) $ + derivingKindError biClass tyConName + + let droppedKindVarNames :: [Name] + droppedKindVarNames = catKindVarNames droppedStarKindStati + + -- Substitute kind * for any dropped kind variables + varTysExpSubst :: [Type] + varTysExpSubst = map (substNamesWithKindStar droppedKindVarNames) varTysExp + + remainingTysExpSubst, droppedTysExpSubst :: [Type] + (remainingTysExpSubst, droppedTysExpSubst) = + splitAt remainingLength varTysExpSubst + + -- All of the type variables mentioned in the dropped types + -- (post-synonym expansion) + droppedTyVarNames :: [Name] + droppedTyVarNames = freeVariables droppedTysExpSubst + + -- If any of the dropped types were polykinded, ensure that they are of kind * + -- after substituting * for the dropped kind variables. If not, throw an error. + unless (all hasKindStar droppedTysExpSubst) $ + derivingKindError biClass tyConName + + let preds :: [Maybe Pred] + kvNames :: [[Name]] + kvNames' :: [Name] + -- Derive instance constraints (and any kind variables which are specialized + -- to * in those constraints) + (preds, kvNames) = unzip $ map (deriveConstraint biClass) remainingTysExpSubst + kvNames' = concat kvNames + + -- Substitute the kind variables specialized in the constraints with * + remainingTysExpSubst' :: [Type] + remainingTysExpSubst' = + map (substNamesWithKindStar kvNames') remainingTysExpSubst + + -- We now substitute all of the specialized-to-* kind variable names with + -- *, but in the original types, not the synonym-expanded types. The reason + -- we do this is a superficial one: we want the derived instance to resemble + -- the datatype written in source code as closely as possible. For example, + -- for the following data family instance: + -- + -- data family Fam a + -- newtype instance Fam String = Fam String + -- + -- We'd want to generate the instance: + -- + -- instance C (Fam String) + -- + -- Not: + -- + -- instance C (Fam [Char]) + remainingTysOrigSubst :: [Type] + remainingTysOrigSubst = + map (substNamesWithKindStar (List.union droppedKindVarNames kvNames')) + $ take remainingLength instTysOrig + + isDataFamily :: Bool + isDataFamily = case variant of + Datatype -> False + Newtype -> False + DataInstance -> True + NewtypeInstance -> True + + remainingTysOrigSubst' :: [Type] + -- See Note [Kind signatures in derived instances] for an explanation + -- of the isDataFamily check. + remainingTysOrigSubst' = + if isDataFamily + then remainingTysOrigSubst + else map unSigT remainingTysOrigSubst + + instanceCxt :: Cxt + instanceCxt = catMaybes preds + + instanceType :: Type + instanceType = AppT (ConT $ biClassName biClass) + $ applyTyCon tyConName remainingTysOrigSubst' + + -- If the datatype context mentions any of the dropped type variables, + -- we can't derive an instance, so throw an error. + when (any (`predMentionsName` droppedTyVarNames) dataCxt) $ + datatypeContextError tyConName instanceType + -- Also ensure the dropped types can be safely eta-reduced. Otherwise, + -- throw an error. + unless (canEtaReduce remainingTysExpSubst' droppedTysExpSubst) $ + etaReductionError instanceType + return (instanceCxt, instanceType) + +-- | Attempt to derive a constraint on a Type. If successful, return +-- Just the constraint and any kind variable names constrained to *. +-- Otherwise, return Nothing and the empty list. +-- +-- See Note [Type inference in derived instances] for the heuristics used to +-- come up with constraints. +deriveConstraint :: BiClass -> Type -> (Maybe Pred, [Name]) +deriveConstraint biClass t + | not (isTyVar t) = (Nothing, []) + | otherwise = case hasKindVarChain 1 t of + Just ns -> ((`applyClass` tName) `fmap` biClassConstraint biClass 1, ns) + _ -> case hasKindVarChain 2 t of + Just ns -> ((`applyClass` tName) `fmap` biClassConstraint biClass 2, ns) + _ -> (Nothing, []) + where + tName :: Name + tName = varTToName t + +{- +Note [Kind signatures in derived instances] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +It is possible to put explicit kind signatures into the derived instances, e.g., + + instance C a => C (Data (f :: * -> *)) where ... + +But it is preferable to avoid this if possible. If we come up with an incorrect +kind signature (which is entirely possible, since our type inferencer is pretty +unsophisticated - see Note [Type inference in derived instances]), then GHC will +flat-out reject the instance, which is quite unfortunate. + +Plain old datatypes have the advantage that you can avoid using any kind signatures +at all in their instances. This is because a datatype declaration uses all type +variables, so the types that we use in a derived instance uniquely determine their +kinds. As long as we plug in the right types, the kind inferencer can do the rest +of the work. For this reason, we use unSigT to remove all kind signatures before +splicing in the instance context and head. + +Data family instances are trickier, since a data family can have two instances that +are distinguished by kind alone, e.g., + + data family Fam (a :: k) + data instance Fam (a :: * -> *) + data instance Fam (a :: *) + +If we dropped the kind signatures for C (Fam a), then GHC will have no way of +knowing which instance we are talking about. To avoid this scenario, we always +include explicit kind signatures in data family instances. There is a chance that +the inferred kind signatures will be incorrect, but if so, we can always fall back +on the make- functions. + +Note [Type inference in derived instances] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Type inference is can be tricky to get right, and we want to avoid recreating the +entirety of GHC's type inferencer in Template Haskell. For this reason, we will +probably never come up with derived instance contexts that are as accurate as +GHC's. But that doesn't mean we can't do anything! There are a couple of simple +things we can do to make instance contexts that work for 80% of use cases: + +1. If one of the last type parameters is polykinded, then its kind will be + specialized to * in the derived instance. We note what kind variable the type + parameter had and substitute it with * in the other types as well. For example, + imagine you had + + data Data (a :: k) (b :: k) (c :: k) + + Then you'd want to derived instance to be: + + instance C (Data (a :: *)) + + Not: + + instance C (Data (a :: k)) + +2. We naïvely come up with instance constraints using the following criteria: + + (i) If there's a type parameter n of kind k1 -> k2 (where k1/k2 are * or kind + variables), then generate a Functor n constraint, and if k1/k2 are kind + variables, then substitute k1/k2 with * elsewhere in the types. We must + consider the case where they are kind variables because you might have a + scenario like this: + + newtype Compose (f :: k3 -> *) (g :: k1 -> k2 -> k3) (a :: k1) (b :: k2) + = Compose (f (g a b)) + + Which would have a derived Bifunctor instance of: + + instance (Functor f, Bifunctor g) => Bifunctor (Compose f g) where ... + (ii) If there's a type parameter n of kind k1 -> k2 -> k3 (where k1/k2/k3 are + * or kind variables), then generate a Bifunctor n constraint and perform + kind substitution as in the other case. +-} + +{- +Note [Matching functions with GADT type variables] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +When deriving Bifoldable, there is a tricky corner case to consider: + + data Both a b where + BothCon :: x -> x -> Both x x + +Which fold functions should be applied to which arguments of BothCon? We have a +choice, since both the function of type (a -> m) and of type (b -> m) can be +applied to either argument. In such a scenario, the second fold function takes +precedence over the first fold function, so the derived Bifoldable instance would be: + + instance Bifoldable Both where + bifoldMap _ g (BothCon x1 x2) = g x1 <> g x2 + +This is not an arbitrary choice, as this definition ensures that +bifoldMap id = Foldable.foldMap for a derived Bifoldable instance for Both. +-} + +------------------------------------------------------------------------------- +-- Error messages +------------------------------------------------------------------------------- + +-- | Either the given data type doesn't have enough type variables, or one of +-- the type variables to be eta-reduced cannot realize kind *. +derivingKindError :: BiClass -> Name -> Q a +derivingKindError biClass tyConName = fail + . showString "Cannot derive well-kinded instance of form ‘" + . showString className + . showChar ' ' + . showParen True + ( showString (nameBase tyConName) + . showString " ..." + ) + . showString "‘\n\tClass " + . showString className + . showString " expects an argument of kind * -> * -> *" + $ "" + where + className :: String + className = nameBase $ biClassName biClass + +-- | One of the last two type variables appeard in a contravariant position +-- when deriving Bifoldable or Bitraversable. +contravarianceError :: Name -> Q a +contravarianceError conName = fail + . showString "Constructor ‘" + . showString (nameBase conName) + . showString "‘ must not use the last type variable(s) in a function argument" + $ "" + +-- | A constructor has a function argument in a derived Bifoldable or Bitraversable +-- instance. +noFunctionsError :: Name -> Q a +noFunctionsError conName = fail + . showString "Constructor ‘" + . showString (nameBase conName) + . showString "‘ must not contain function types" + $ "" + +-- | The data type has a DatatypeContext which mentions one of the eta-reduced +-- type variables. +datatypeContextError :: Name -> Type -> Q a +datatypeContextError dataName instanceType = fail + . showString "Can't make a derived instance of ‘" + . showString (pprint instanceType) + . showString "‘:\n\tData type ‘" + . showString (nameBase dataName) + . showString "‘ must not have a class context involving the last type argument(s)" + $ "" + +-- | The data type has an existential constraint which mentions one of the +-- eta-reduced type variables. +existentialContextError :: Name -> Q a +existentialContextError conName = fail + . showString "Constructor ‘" + . showString (nameBase conName) + . showString "‘ must be truly polymorphic in the last argument(s) of the data type" + $ "" + +-- | The data type mentions one of the n eta-reduced type variables in a place other +-- than the last nth positions of a data type in a constructor's field. +outOfPlaceTyVarError :: Name -> Q a +outOfPlaceTyVarError conName = fail + . showString "Constructor ‘" + . showString (nameBase conName) + . showString "‘ must only use its last two type variable(s) within" + . showString " the last two argument(s) of a data type" + $ "" + +-- | One of the last type variables cannot be eta-reduced (see the canEtaReduce +-- function for the criteria it would have to meet). +etaReductionError :: Type -> Q a +etaReductionError instanceType = fail $ + "Cannot eta-reduce to an instance of form \n\tinstance (...) => " + ++ pprint instanceType + +------------------------------------------------------------------------------- +-- Class-specific constants +------------------------------------------------------------------------------- + +-- | A representation of which class is being derived. +data BiClass = Bifunctor | Bifoldable | Bitraversable + +-- | A representation of which function is being generated. +data BiFun = Bimap | Bifoldr | BifoldMap | Bitraverse + deriving Eq + +biFunConstName :: BiFun -> Name +biFunConstName Bimap = bimapConstValName +biFunConstName Bifoldr = bifoldrConstValName +biFunConstName BifoldMap = bifoldMapConstValName +biFunConstName Bitraverse = bitraverseConstValName + +biClassName :: BiClass -> Name +biClassName Bifunctor = bifunctorTypeName +biClassName Bifoldable = bifoldableTypeName +biClassName Bitraversable = bitraversableTypeName + +biFunName :: BiFun -> Name +biFunName Bimap = bimapValName +biFunName Bifoldr = bifoldrValName +biFunName BifoldMap = bifoldMapValName +biFunName Bitraverse = bitraverseValName + +biClassToFuns :: BiClass -> [BiFun] +biClassToFuns Bifunctor = [Bimap] +biClassToFuns Bifoldable = [Bifoldr, BifoldMap] +biClassToFuns Bitraversable = [Bitraverse] + +biFunToClass :: BiFun -> BiClass +biFunToClass Bimap = Bifunctor +biFunToClass Bifoldr = Bifoldable +biFunToClass BifoldMap = Bifoldable +biFunToClass Bitraverse = Bitraversable + +biClassConstraint :: BiClass -> Int -> Maybe Name +biClassConstraint Bifunctor 1 = Just functorTypeName +biClassConstraint Bifoldable 1 = Just foldableTypeName +biClassConstraint Bitraversable 1 = Just traversableTypeName +biClassConstraint biClass 2 = Just $ biClassName biClass +biClassConstraint _ _ = Nothing + +fmapArity :: Int -> Name +fmapArity 1 = fmapValName +fmapArity 2 = bimapValName +fmapArity n = arityErr n + +foldrArity :: Int -> Name +foldrArity 1 = foldrValName +foldrArity 2 = bifoldrValName +foldrArity n = arityErr n + +foldMapArity :: Int -> Name +foldMapArity 1 = foldMapValName +foldMapArity 2 = bifoldMapValName +foldMapArity n = arityErr n + +traverseArity :: Int -> Name +traverseArity 1 = traverseValName +traverseArity 2 = bitraverseValName +traverseArity n = arityErr n + +arityErr :: Int -> a +arityErr n = error $ "Unsupported arity: " ++ show n + +allowExQuant :: BiClass -> Bool +allowExQuant Bifoldable = True +allowExQuant _ = False + +biFunEmptyCase :: BiFun -> Name -> Name -> Q Exp +biFunEmptyCase biFun z value = + biFunTrivial emptyCase + (varE pureValName `appE` emptyCase) + biFun z + where + emptyCase :: Q Exp + emptyCase = caseE (varE value) [] + +biFunNoCons :: BiFun -> Name -> Name -> Q Exp +biFunNoCons biFun z value = + biFunTrivial seqAndError + (varE pureValName `appE` seqAndError) + biFun z + where + seqAndError :: Q Exp + seqAndError = appE (varE seqValName) (varE value) `appE` + appE (varE errorValName) + (stringE $ "Void " ++ nameBase (biFunName biFun)) + +biFunTrivial :: Q Exp -> Q Exp -> BiFun -> Name -> Q Exp +biFunTrivial bimapE bitraverseE biFun z = go biFun + where + go :: BiFun -> Q Exp + go Bimap = bimapE + go Bifoldr = varE z + go BifoldMap = varE memptyValName + go Bitraverse = bitraverseE + +{- +Note [ft_triv for Bifoldable and Bitraversable] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +When deriving Bifoldable and Bitraversable, we filter out any subexpressions whose +type does not mention one of the last two type parameters. From this, you might +think that we don't need to implement ft_triv for bifoldr, bifoldMap, or +bitraverse at all, but in fact we do need to. Imagine the following data type: + + data T a b = MkT a (T Int b) + +In a derived Bifoldable T instance, you would generate the following bifoldMap +definition: + + bifoldMap f g (MkT a1 a2) = f a1 <> bifoldMap (\_ -> mempty) g arg2 + +You need to fill in bi_triv (\_ -> mempty) as the first argument to the recursive +call to bifoldMap, since that is how the algorithm handles polymorphic recursion. +-} + +------------------------------------------------------------------------------- +-- Generic traversal for functor-like deriving +------------------------------------------------------------------------------- + +-- Much of the code below is cargo-culted from the TcGenFunctor module in GHC. + +data FFoldType a -- Describes how to fold over a Type in a functor like way + = FT { ft_triv :: a + -- ^ Does not contain variables + , ft_var :: Name -> a + -- ^ A bare variable + , ft_co_var :: Name -> a + -- ^ A bare variable, contravariantly + , ft_fun :: a -> a -> a + -- ^ Function type + , ft_tup :: TupleSort -> [a] -> a + -- ^ Tuple type. The [a] is the result of folding over the + -- arguments of the tuple. + , ft_ty_app :: [(Type, a)] -> a + -- ^ Type app, variables only in last argument. The [(Type, a)] + -- represents the last argument types. That is, they form the + -- argument parts of @fun_ty arg_ty_1 ... arg_ty_n@. + , ft_bad_app :: a + -- ^ Type app, variable other than in last arguments + , ft_forall :: [TyVarBndrSpec] -> a -> a + -- ^ Forall type + } + +-- Note that in GHC, this function is pure. It must be monadic here since we: +-- +-- (1) Expand type synonyms +-- (2) Detect type family applications +-- +-- Which require reification in Template Haskell, but are pure in Core. +functorLikeTraverse :: forall a. + TyVarMap -- ^ Variables to look for + -> FFoldType a -- ^ How to fold + -> Type -- ^ Type to process + -> Q a +functorLikeTraverse tvMap (FT { ft_triv = caseTrivial, ft_var = caseVar + , ft_co_var = caseCoVar, ft_fun = caseFun + , ft_tup = caseTuple, ft_ty_app = caseTyApp + , ft_bad_app = caseWrongArg, ft_forall = caseForAll }) + ty + = do ty' <- resolveTypeSynonyms ty + (res, _) <- go False ty' + return res + where + go :: Bool -- Covariant or contravariant context + -> Type + -> Q (a, Bool) -- (result of type a, does type contain var) + go co t@AppT{} + | (ArrowT, [funArg, funRes]) <- unapplyTy t + = do (funArgR, funArgC) <- go (not co) funArg + (funResR, funResC) <- go co funRes + if funArgC || funResC + then return (caseFun funArgR funResR, True) + else trivial + go co t@AppT{} = do + let (f, args) = unapplyTy t + (_, fc) <- go co f + (xrs, xcs) <- fmap unzip $ mapM (go co) args + let numLastArgs, numFirstArgs :: Int + numLastArgs = min 2 $ length args + numFirstArgs = length args - numLastArgs + + tuple :: TupleSort -> Q (a, Bool) + tuple tupSort = return (caseTuple tupSort xrs, True) + + wrongArg :: Q (a, Bool) + wrongArg = return (caseWrongArg, True) + + case () of + _ | not (or xcs) + -> trivial -- Variable does not occur + -- At this point we know that xrs, xcs is not empty, + -- and at least one xr is True + | TupleT len <- f + -> tuple $ Boxed len +#if MIN_VERSION_template_haskell(2,6,0) + | UnboxedTupleT len <- f + -> tuple $ Unboxed len +#endif + | fc || or (take numFirstArgs xcs) + -> wrongArg -- T (..var..) ty_1 ... ty_n + | otherwise -- T (..no var..) ty_1 ... ty_n + -> do itf <- isInTypeFamilyApp tyVarNames f args + if itf -- We can't decompose type families, so + -- error if we encounter one here. + then wrongArg + else return ( caseTyApp $ drop numFirstArgs $ zip args xrs + , True ) + go co (SigT t k) = do + (_, kc) <- go_kind co k + if kc + then return (caseWrongArg, True) + else go co t + go co (VarT v) + | Map.member v tvMap + = return (if co then caseCoVar v else caseVar v, True) + | otherwise + = trivial + go co (ForallT tvbs _ t) = do + (tr, tc) <- go co t + let tvbNames = map tvName tvbs + if not tc || any (`elem` tvbNames) tyVarNames + then trivial + else return (caseForAll tvbs tr, True) + go _ _ = trivial + + go_kind :: Bool + -> Kind + -> Q (a, Bool) +#if MIN_VERSION_template_haskell(2,9,0) + go_kind = go +#else + go_kind _ _ = trivial +#endif + + trivial :: Q (a, Bool) + trivial = return (caseTrivial, False) + + tyVarNames :: [Name] + tyVarNames = Map.keys tvMap + +-- Fold over the arguments of a data constructor in a Functor-like way. +foldDataConArgs :: forall a. TyVarMap -> FFoldType a -> ConstructorInfo -> Q [a] +foldDataConArgs tvMap ft con = do + fieldTys <- mapM resolveTypeSynonyms $ constructorFields con + mapM foldArg fieldTys + where + foldArg :: Type -> Q a + foldArg = functorLikeTraverse tvMap ft + +-- Make a 'LamE' using a fresh variable. +mkSimpleLam :: (Exp -> Q Exp) -> Q Exp +mkSimpleLam lam = do + -- Use an underscore in front of the variable name, as it's possible for + -- certain Bifoldable instances to generate code like this (see #89): + -- + -- @ + -- bifoldMap (\\_n -> mempty) ... + -- @ + -- + -- Without the underscore, that code would trigger -Wunused-matches warnings. + n <- newName "_n" + body <- lam (VarE n) + return $ LamE [VarP n] body + +-- Make a 'LamE' using two fresh variables. +mkSimpleLam2 :: (Exp -> Exp -> Q Exp) -> Q Exp +mkSimpleLam2 lam = do + -- Use an underscore in front of the variable name, as it's possible for + -- certain Bifoldable instances to generate code like this (see #89): + -- + -- @ + -- bifoldr (\\_n1 n2 -> n2) ... + -- @ + -- + -- Without the underscore, that code would trigger -Wunused-matches warnings. + n1 <- newName "_n1" + n2 <- newName "n2" + body <- lam (VarE n1) (VarE n2) + return $ LamE [VarP n1, VarP n2] body + +-- "Con a1 a2 a3 -> fold [x1 a1, x2 a2, x3 a3]" +-- +-- @mkSimpleConMatch fold conName insides@ produces a match clause in +-- which the LHS pattern-matches on @extraPats@, followed by a match on the +-- constructor @conName@ and its arguments. The RHS folds (with @fold@) over +-- @conName@ and its arguments, applying an expression (from @insides@) to each +-- of the respective arguments of @conName@. +mkSimpleConMatch :: (Name -> [a] -> Q Exp) + -> Name + -> [Exp -> a] + -> Q Match +mkSimpleConMatch fold conName insides = do + varsNeeded <- newNameList "_arg" $ length insides + let pat = conPCompat conName (map VarP varsNeeded) + rhs <- fold conName (zipWith (\i v -> i $ VarE v) insides varsNeeded) + return $ Match pat (NormalB rhs) [] + +-- "Con a1 a2 a3 -> fmap (\b2 -> Con a1 b2 a3) (traverse f a2)" +-- +-- @mkSimpleConMatch2 fold conName insides@ behaves very similarly to +-- 'mkSimpleConMatch', with two key differences: +-- +-- 1. @insides@ is a @[(Bool, Exp)]@ instead of a @[Exp]@. This is because it +-- filters out the expressions corresponding to arguments whose types do not +-- mention the last type variable in a derived 'Foldable' or 'Traversable' +-- instance (i.e., those elements of @insides@ containing @False@). +-- +-- 2. @fold@ takes an expression as its first argument instead of a +-- constructor name. This is because it uses a specialized +-- constructor function expression that only takes as many parameters as +-- there are argument types that mention the last type variable. +mkSimpleConMatch2 :: (Exp -> [Exp] -> Q Exp) + -> Name + -> [(Bool, Exp)] + -> Q Match +mkSimpleConMatch2 fold conName insides = do + varsNeeded <- newNameList "_arg" lengthInsides + let pat = conPCompat conName (map VarP varsNeeded) + -- Make sure to zip BEFORE invoking catMaybes. We want the variable + -- indicies in each expression to match up with the argument indices + -- in conExpr (defined below). + exps = catMaybes $ zipWith (\(m, i) v -> if m then Just (i `AppE` VarE v) + else Nothing) + insides varsNeeded + -- An element of argTysTyVarInfo is True if the constructor argument + -- with the same index has a type which mentions the last type + -- variable. + argTysTyVarInfo = map (\(m, _) -> m) insides + (asWithTyVar, asWithoutTyVar) = partitionByList argTysTyVarInfo varsNeeded + + conExpQ + | null asWithTyVar = appsE (conE conName:map varE asWithoutTyVar) + | otherwise = do + bs <- newNameList "b" lengthInsides + let bs' = filterByList argTysTyVarInfo bs + vars = filterByLists argTysTyVarInfo + (map varE bs) (map varE varsNeeded) + lamE (map varP bs') (appsE (conE conName:vars)) + + conExp <- conExpQ + rhs <- fold conExp exps + return $ Match pat (NormalB rhs) [] + where + lengthInsides = length insides + +-- Indicates whether a tuple is boxed or unboxed, as well as its number of +-- arguments. For instance, (a, b) corresponds to @Boxed 2@, and (# a, b, c #) +-- corresponds to @Unboxed 3@. +data TupleSort + = Boxed Int +#if MIN_VERSION_template_haskell(2,6,0) + | Unboxed Int +#endif + +-- "case x of (a1,a2,a3) -> fold [x1 a1, x2 a2, x3 a3]" +mkSimpleTupleCase :: (Name -> [a] -> Q Match) + -> TupleSort -> [a] -> Exp -> Q Exp +mkSimpleTupleCase matchForCon tupSort insides x = do + let tupDataName = case tupSort of + Boxed len -> tupleDataName len +#if MIN_VERSION_template_haskell(2,6,0) + Unboxed len -> unboxedTupleDataName len +#endif + m <- matchForCon tupDataName insides + return $ CaseE x [m] + +-- Adapt to the type of ConP changing in template-haskell-2.18.0.0. +conPCompat :: Name -> [Pat] -> Pat +conPCompat n pats = ConP n +#if MIN_VERSION_template_haskell(2,18,0) + [] +#endif + pats diff --git a/src/Data/Bifunctor/TH/Internal.hs b/src/Data/Bifunctor/TH/Internal.hs --- a/src/Data/Bifunctor/TH/Internal.hs +++ b/src/Data/Bifunctor/TH/Internal.hs @@ -1,574 +1,574 @@ -{-# LANGUAGE CPP #-} - -#if __GLASGOW_HASKELL__ >= 704 -{-# LANGUAGE Unsafe #-} -#endif - -{-| -Module: Data.Bifunctor.TH.Internal -Copyright: (C) 2008-2016 Edward Kmett, (C) 2015-2016 Ryan Scott -License: BSD-style (see the file LICENSE) -Maintainer: Edward Kmett -Portability: Template Haskell - -Template Haskell-related utilities. --} -module Data.Bifunctor.TH.Internal where - -import Data.Foldable (foldr') -import qualified Data.List as List -import qualified Data.Map as Map (singleton) -import Data.Map (Map) -import Data.Maybe (fromMaybe, mapMaybe) -import qualified Data.Set as Set -import Data.Set (Set) - -import Language.Haskell.TH.Datatype -import Language.Haskell.TH.Lib -import Language.Haskell.TH.Syntax - --- Ensure, beyond a shadow of a doubt, that the instances are in-scope -import Data.Bifunctor () -import Data.Bifoldable () -import Data.Bitraversable () - -#ifndef CURRENT_PACKAGE_KEY -import Data.Version (showVersion) -import Paths_bifunctors (version) -#endif - -------------------------------------------------------------------------------- --- Expanding type synonyms -------------------------------------------------------------------------------- - -applySubstitutionKind :: Map Name Kind -> Type -> Type -#if MIN_VERSION_template_haskell(2,8,0) -applySubstitutionKind = applySubstitution -#else -applySubstitutionKind _ t = t -#endif - -substNameWithKind :: Name -> Kind -> Type -> Type -substNameWithKind n k = applySubstitutionKind (Map.singleton n k) - -substNamesWithKindStar :: [Name] -> Type -> Type -substNamesWithKindStar ns t = foldr' (flip substNameWithKind starK) t ns - -------------------------------------------------------------------------------- --- Type-specialized const functions -------------------------------------------------------------------------------- - -bimapConst :: p b d -> (a -> b) -> (c -> d) -> p a c -> p b d -bimapConst = const . const . const -{-# INLINE bimapConst #-} - -bifoldrConst :: c -> (a -> c -> c) -> (b -> c -> c) -> c -> p a b -> c -bifoldrConst = const . const . const . const -{-# INLINE bifoldrConst #-} - -bifoldMapConst :: m -> (a -> m) -> (b -> m) -> p a b -> m -bifoldMapConst = const . const . const -{-# INLINE bifoldMapConst #-} - -bitraverseConst :: f (t c d) -> (a -> f c) -> (b -> f d) -> t a b -> f (t c d) -bitraverseConst = const . const . const -{-# INLINE bitraverseConst #-} - -------------------------------------------------------------------------------- --- StarKindStatus -------------------------------------------------------------------------------- - --- | Whether a type is not of kind *, is of kind *, or is a kind variable. -data StarKindStatus = NotKindStar - | KindStar - | IsKindVar Name - deriving Eq - --- | Does a Type have kind * or k (for some kind variable k)? -canRealizeKindStar :: Type -> StarKindStatus -canRealizeKindStar t - | hasKindStar t = KindStar - | otherwise = case t of -#if MIN_VERSION_template_haskell(2,8,0) - SigT _ (VarT k) -> IsKindVar k -#endif - _ -> NotKindStar - --- | Returns 'Just' the kind variable 'Name' of a 'StarKindStatus' if it exists. --- Otherwise, returns 'Nothing'. -starKindStatusToName :: StarKindStatus -> Maybe Name -starKindStatusToName (IsKindVar n) = Just n -starKindStatusToName _ = Nothing - --- | Concat together all of the StarKindStatuses that are IsKindVar and extract --- the kind variables' Names out. -catKindVarNames :: [StarKindStatus] -> [Name] -catKindVarNames = mapMaybe starKindStatusToName - -------------------------------------------------------------------------------- --- Assorted utilities -------------------------------------------------------------------------------- - --- filterByList, filterByLists, and partitionByList taken from GHC (BSD3-licensed) - --- | 'filterByList' takes a list of Bools and a list of some elements and --- filters out these elements for which the corresponding value in the list of --- Bools is False. This function does not check whether the lists have equal --- length. -filterByList :: [Bool] -> [a] -> [a] -filterByList (True:bs) (x:xs) = x : filterByList bs xs -filterByList (False:bs) (_:xs) = filterByList bs xs -filterByList _ _ = [] - --- | 'filterByLists' takes a list of Bools and two lists as input, and --- outputs a new list consisting of elements from the last two input lists. For --- each Bool in the list, if it is 'True', then it takes an element from the --- former list. If it is 'False', it takes an element from the latter list. --- The elements taken correspond to the index of the Bool in its list. --- For example: --- --- @ --- filterByLists [True, False, True, False] \"abcd\" \"wxyz\" = \"axcz\" --- @ --- --- This function does not check whether the lists have equal length. -filterByLists :: [Bool] -> [a] -> [a] -> [a] -filterByLists (True:bs) (x:xs) (_:ys) = x : filterByLists bs xs ys -filterByLists (False:bs) (_:xs) (y:ys) = y : filterByLists bs xs ys -filterByLists _ _ _ = [] - --- | 'partitionByList' takes a list of Bools and a list of some elements and --- partitions the list according to the list of Bools. Elements corresponding --- to 'True' go to the left; elements corresponding to 'False' go to the right. --- For example, @partitionByList [True, False, True] [1,2,3] == ([1,3], [2])@ --- This function does not check whether the lists have equal --- length. -partitionByList :: [Bool] -> [a] -> ([a], [a]) -partitionByList = go [] [] - where - go trues falses (True : bs) (x : xs) = go (x:trues) falses bs xs - go trues falses (False : bs) (x : xs) = go trues (x:falses) bs xs - go trues falses _ _ = (reverse trues, reverse falses) - --- | Returns True if a Type has kind *. -hasKindStar :: Type -> Bool -hasKindStar VarT{} = True -#if MIN_VERSION_template_haskell(2,8,0) -hasKindStar (SigT _ StarT) = True -#else -hasKindStar (SigT _ StarK) = True -#endif -hasKindStar _ = False - --- Returns True is a kind is equal to *, or if it is a kind variable. -isStarOrVar :: Kind -> Bool -#if MIN_VERSION_template_haskell(2,8,0) -isStarOrVar StarT = True -isStarOrVar VarT{} = True -#else -isStarOrVar StarK = True -#endif -isStarOrVar _ = False - --- | @hasKindVarChain n kind@ Checks if @kind@ is of the form --- k_0 -> k_1 -> ... -> k_(n-1), where k0, k1, ..., and k_(n-1) can be * or --- kind variables. -hasKindVarChain :: Int -> Type -> Maybe [Name] -hasKindVarChain kindArrows t = - let uk = uncurryKind (tyKind t) - in if (length uk - 1 == kindArrows) && all isStarOrVar uk - then Just (freeVariables uk) - else Nothing - --- | If a Type is a SigT, returns its kind signature. Otherwise, return *. -tyKind :: Type -> Kind -tyKind (SigT _ k) = k -tyKind _ = starK - --- | A mapping of type variable Names to their map function Names. For example, in a --- Bifunctor declaration, a TyVarMap might look like (a ~> f, b ~> g), where --- a and b are the last two type variables of the datatype, and f and g are the two --- functions which map their respective type variables. -type TyVarMap = Map Name Name - -thd3 :: (a, b, c) -> c -thd3 (_, _, c) = c - -unsnoc :: [a] -> Maybe ([a], a) -unsnoc [] = Nothing -unsnoc (x:xs) = case unsnoc xs of - Nothing -> Just ([], x) - Just (a,b) -> Just (x:a, b) - --- | Generate a list of fresh names with a common prefix, and numbered suffixes. -newNameList :: String -> Int -> Q [Name] -newNameList prefix n = mapM (newName . (prefix ++) . show) [1..n] - --- | Applies a typeclass constraint to a type. -applyClass :: Name -> Name -> Pred -#if MIN_VERSION_template_haskell(2,10,0) -applyClass con t = AppT (ConT con) (VarT t) -#else -applyClass con t = ClassP con [VarT t] -#endif - --- | Checks to see if the last types in a data family instance can be safely eta- --- reduced (i.e., dropped), given the other types. This checks for three conditions: --- --- (1) All of the dropped types are type variables --- (2) All of the dropped types are distinct --- (3) None of the remaining types mention any of the dropped types -canEtaReduce :: [Type] -> [Type] -> Bool -canEtaReduce remaining dropped = - all isTyVar dropped - && allDistinct droppedNames -- Make sure not to pass something of type [Type], since Type - -- didn't have an Ord instance until template-haskell-2.10.0.0 - && not (any (`mentionsName` droppedNames) remaining) - where - droppedNames :: [Name] - droppedNames = map varTToName dropped - --- | Extract Just the Name from a type variable. If the argument Type is not a --- type variable, return Nothing. -varTToName_maybe :: Type -> Maybe Name -varTToName_maybe (VarT n) = Just n -varTToName_maybe (SigT t _) = varTToName_maybe t -varTToName_maybe _ = Nothing - --- | Extract the Name from a type variable. If the argument Type is not a --- type variable, throw an error. -varTToName :: Type -> Name -varTToName = fromMaybe (error "Not a type variable!") . varTToName_maybe - --- | Peel off a kind signature from a Type (if it has one). -unSigT :: Type -> Type -unSigT (SigT t _) = t -unSigT t = t - --- | Is the given type a variable? -isTyVar :: Type -> Bool -isTyVar (VarT _) = True -isTyVar (SigT t _) = isTyVar t -isTyVar _ = False - --- | Detect if a Name in a list of provided Names occurs as an argument to some --- type family. This makes an effort to exclude /oversaturated/ arguments to --- type families. For instance, if one declared the following type family: --- --- @ --- type family F a :: Type -> Type --- @ --- --- Then in the type @F a b@, we would consider @a@ to be an argument to @F@, --- but not @b@. -isInTypeFamilyApp :: [Name] -> Type -> [Type] -> Q Bool -isInTypeFamilyApp names tyFun tyArgs = - case tyFun of - ConT tcName -> go tcName - _ -> return False - where - go :: Name -> Q Bool - go tcName = do - info <- reify tcName - case info of -#if MIN_VERSION_template_haskell(2,11,0) - FamilyI (OpenTypeFamilyD (TypeFamilyHead _ bndrs _ _)) _ - -> withinFirstArgs bndrs -#elif MIN_VERSION_template_haskell(2,7,0) - FamilyI (FamilyD TypeFam _ bndrs _) _ - -> withinFirstArgs bndrs -#else - TyConI (FamilyD TypeFam _ bndrs _) - -> withinFirstArgs bndrs -#endif - -#if MIN_VERSION_template_haskell(2,11,0) - FamilyI (ClosedTypeFamilyD (TypeFamilyHead _ bndrs _ _) _) _ - -> withinFirstArgs bndrs -#elif MIN_VERSION_template_haskell(2,9,0) - FamilyI (ClosedTypeFamilyD _ bndrs _ _) _ - -> withinFirstArgs bndrs -#endif - - _ -> return False - where - withinFirstArgs :: [a] -> Q Bool - withinFirstArgs bndrs = - let firstArgs = take (length bndrs) tyArgs - argFVs = freeVariables firstArgs - in return $ any (`elem` argFVs) names - --- | Are all of the items in a list (which have an ordering) distinct? --- --- This uses Set (as opposed to nub) for better asymptotic time complexity. -allDistinct :: Ord a => [a] -> Bool -allDistinct = allDistinct' Set.empty - where - allDistinct' :: Ord a => Set a -> [a] -> Bool - allDistinct' uniqs (x:xs) - | x `Set.member` uniqs = False - | otherwise = allDistinct' (Set.insert x uniqs) xs - allDistinct' _ _ = True - --- | Does the given type mention any of the Names in the list? -mentionsName :: Type -> [Name] -> Bool -mentionsName = go - where - go :: Type -> [Name] -> Bool - go (AppT t1 t2) names = go t1 names || go t2 names - go (SigT t _k) names = go t names -#if MIN_VERSION_template_haskell(2,8,0) - || go _k names -#endif - go (VarT n) names = n `elem` names - go _ _ = False - --- | Does an instance predicate mention any of the Names in the list? -predMentionsName :: Pred -> [Name] -> Bool -#if MIN_VERSION_template_haskell(2,10,0) -predMentionsName = mentionsName -#else -predMentionsName (ClassP n tys) names = n `elem` names || any (`mentionsName` names) tys -predMentionsName (EqualP t1 t2) names = mentionsName t1 names || mentionsName t2 names -#endif - --- | Construct a type via curried application. -applyTy :: Type -> [Type] -> Type -applyTy = List.foldl' AppT - --- | Fully applies a type constructor to its type variables. -applyTyCon :: Name -> [Type] -> Type -applyTyCon = applyTy . ConT - --- | Split an applied type into its individual components. For example, this: --- --- @ --- Either Int Char --- @ --- --- would split to this: --- --- @ --- [Either, Int, Char] --- @ -unapplyTy :: Type -> (Type, [Type]) -unapplyTy ty = go ty ty [] - where - go :: Type -> Type -> [Type] -> (Type, [Type]) - go _ (AppT ty1 ty2) args = go ty1 ty1 (ty2:args) - go origTy (SigT ty' _) args = go origTy ty' args -#if MIN_VERSION_template_haskell(2,11,0) - go origTy (InfixT ty1 n ty2) args = go origTy (ConT n `AppT` ty1 `AppT` ty2) args - go origTy (ParensT ty') args = go origTy ty' args -#endif - go origTy _ args = (origTy, args) - --- | Split a type signature by the arrows on its spine. For example, this: --- --- @ --- forall a b. (a ~ b) => (a -> b) -> Char -> () --- @ --- --- would split to this: --- --- @ --- (a ~ b, [a -> b, Char, ()]) --- @ -uncurryTy :: Type -> (Cxt, [Type]) -uncurryTy (AppT (AppT ArrowT t1) t2) = - let (ctxt, tys) = uncurryTy t2 - in (ctxt, t1:tys) -uncurryTy (SigT t _) = uncurryTy t -uncurryTy (ForallT _ ctxt t) = - let (ctxt', tys) = uncurryTy t - in (ctxt ++ ctxt', tys) -uncurryTy t = ([], [t]) - --- | Like uncurryType, except on a kind level. -uncurryKind :: Kind -> [Kind] -#if MIN_VERSION_template_haskell(2,8,0) -uncurryKind = snd . uncurryTy -#else -uncurryKind (ArrowK k1 k2) = k1:uncurryKind k2 -uncurryKind k = [k] -#endif - -------------------------------------------------------------------------------- --- Manually quoted names -------------------------------------------------------------------------------- - --- By manually generating these names we avoid needing to use the --- TemplateHaskell language extension when compiling the bifunctors library. --- This allows the library to be used in stage1 cross-compilers. - -bifunctorsPackageKey :: String -#ifdef CURRENT_PACKAGE_KEY -bifunctorsPackageKey = CURRENT_PACKAGE_KEY -#else -bifunctorsPackageKey = "bifunctors-" ++ showVersion version -#endif - -mkBifunctorsName_tc :: String -> String -> Name -mkBifunctorsName_tc = mkNameG_tc bifunctorsPackageKey - -mkBifunctorsName_v :: String -> String -> Name -mkBifunctorsName_v = mkNameG_v bifunctorsPackageKey - -bimapConstValName :: Name -bimapConstValName = mkBifunctorsName_v "Data.Bifunctor.TH.Internal" "bimapConst" - -bifoldrConstValName :: Name -bifoldrConstValName = mkBifunctorsName_v "Data.Bifunctor.TH.Internal" "bifoldrConst" - -bifoldMapConstValName :: Name -bifoldMapConstValName = mkBifunctorsName_v "Data.Bifunctor.TH.Internal" "bifoldMapConst" - -coerceValName :: Name -coerceValName = mkNameG_v "ghc-prim" "GHC.Prim" "coerce" - -bitraverseConstValName :: Name -bitraverseConstValName = mkBifunctorsName_v "Data.Bifunctor.TH.Internal" "bitraverseConst" - -wrapMonadDataName :: Name -wrapMonadDataName = mkNameG_d "base" "Control.Applicative" "WrapMonad" - -functorTypeName :: Name -functorTypeName = mkNameG_tc "base" "GHC.Base" "Functor" - -foldableTypeName :: Name -foldableTypeName = mkNameG_tc "base" "Data.Foldable" "Foldable" - -traversableTypeName :: Name -traversableTypeName = mkNameG_tc "base" "Data.Traversable" "Traversable" - -composeValName :: Name -composeValName = mkNameG_v "base" "GHC.Base" "." - -idValName :: Name -idValName = mkNameG_v "base" "GHC.Base" "id" - -errorValName :: Name -errorValName = mkNameG_v "base" "GHC.Err" "error" - -flipValName :: Name -flipValName = mkNameG_v "base" "GHC.Base" "flip" - -fmapValName :: Name -fmapValName = mkNameG_v "base" "GHC.Base" "fmap" - -foldrValName :: Name -foldrValName = mkNameG_v "base" "Data.Foldable" "foldr" - -foldMapValName :: Name -foldMapValName = mkNameG_v "base" "Data.Foldable" "foldMap" - -seqValName :: Name -seqValName = mkNameG_v "ghc-prim" "GHC.Prim" "seq" - -traverseValName :: Name -traverseValName = mkNameG_v "base" "Data.Traversable" "traverse" - -unwrapMonadValName :: Name -unwrapMonadValName = mkNameG_v "base" "Control.Applicative" "unwrapMonad" - -#if MIN_VERSION_base(4,8,0) -bifunctorTypeName :: Name -bifunctorTypeName = mkNameG_tc "base" "Data.Bifunctor" "Bifunctor" - -bimapValName :: Name -bimapValName = mkNameG_v "base" "Data.Bifunctor" "bimap" - -pureValName :: Name -pureValName = mkNameG_v "base" "GHC.Base" "pure" - -apValName :: Name -apValName = mkNameG_v "base" "GHC.Base" "<*>" - -liftA2ValName :: Name -liftA2ValName = mkNameG_v "base" "GHC.Base" "liftA2" - -mappendValName :: Name -mappendValName = mkNameG_v "base" "GHC.Base" "mappend" - -memptyValName :: Name -memptyValName = mkNameG_v "base" "GHC.Base" "mempty" -#else -bifunctorTypeName :: Name -bifunctorTypeName = mkBifunctorsName_tc "Data.Bifunctor" "Bifunctor" - -bimapValName :: Name -bimapValName = mkBifunctorsName_v "Data.Bifunctor" "bimap" - -pureValName :: Name -pureValName = mkNameG_v "base" "Control.Applicative" "pure" - -apValName :: Name -apValName = mkNameG_v "base" "Control.Applicative" "<*>" - -liftA2ValName :: Name -liftA2ValName = mkNameG_v "base" "Control.Applicative" "liftA2" - -mappendValName :: Name -mappendValName = mkNameG_v "base" "Data.Monoid" "mappend" - -memptyValName :: Name -memptyValName = mkNameG_v "base" "Data.Monoid" "mempty" -#endif - -#if MIN_VERSION_base(4,10,0) -bifoldableTypeName :: Name -bifoldableTypeName = mkNameG_tc "base" "Data.Bifoldable" "Bifoldable" - -bitraversableTypeName :: Name -bitraversableTypeName = mkNameG_tc "base" "Data.Bitraversable" "Bitraversable" - -bifoldrValName :: Name -bifoldrValName = mkNameG_v "base" "Data.Bifoldable" "bifoldr" - -bifoldMapValName :: Name -bifoldMapValName = mkNameG_v "base" "Data.Bifoldable" "bifoldMap" - -bitraverseValName :: Name -bitraverseValName = mkNameG_v "base" "Data.Bitraversable" "bitraverse" -#else -bifoldableTypeName :: Name -bifoldableTypeName = mkBifunctorsName_tc "Data.Bifoldable" "Bifoldable" - -bitraversableTypeName :: Name -bitraversableTypeName = mkBifunctorsName_tc "Data.Bitraversable" "Bitraversable" - -bifoldrValName :: Name -bifoldrValName = mkBifunctorsName_v "Data.Bifoldable" "bifoldr" - -bifoldMapValName :: Name -bifoldMapValName = mkBifunctorsName_v "Data.Bifoldable" "bifoldMap" - -bitraverseValName :: Name -bitraverseValName = mkBifunctorsName_v "Data.Bitraversable" "bitraverse" -#endif - -#if MIN_VERSION_base(4,11,0) -appEndoValName :: Name -appEndoValName = mkNameG_v "base" "Data.Semigroup.Internal" "appEndo" - -dualDataName :: Name -dualDataName = mkNameG_d "base" "Data.Semigroup.Internal" "Dual" - -endoDataName :: Name -endoDataName = mkNameG_d "base" "Data.Semigroup.Internal" "Endo" - -getDualValName :: Name -getDualValName = mkNameG_v "base" "Data.Semigroup.Internal" "getDual" -#else -appEndoValName :: Name -appEndoValName = mkNameG_v "base" "Data.Monoid" "appEndo" - -dualDataName :: Name -dualDataName = mkNameG_d "base" "Data.Monoid" "Dual" - -endoDataName :: Name -endoDataName = mkNameG_d "base" "Data.Monoid" "Endo" - -getDualValName :: Name -getDualValName = mkNameG_v "base" "Data.Monoid" "getDual" -#endif +{-# LANGUAGE CPP #-} + +#if __GLASGOW_HASKELL__ >= 704 +{-# LANGUAGE Unsafe #-} +#endif + +{-| +Module: Data.Bifunctor.TH.Internal +Copyright: (C) 2008-2016 Edward Kmett, (C) 2015-2016 Ryan Scott +License: BSD-style (see the file LICENSE) +Maintainer: Edward Kmett +Portability: Template Haskell + +Template Haskell-related utilities. +-} +module Data.Bifunctor.TH.Internal where + +import Data.Foldable (foldr') +import qualified Data.List as List +import qualified Data.Map as Map (singleton) +import Data.Map (Map) +import Data.Maybe (fromMaybe, mapMaybe) +import qualified Data.Set as Set +import Data.Set (Set) + +import Language.Haskell.TH.Datatype +import Language.Haskell.TH.Lib +import Language.Haskell.TH.Syntax + +-- Ensure, beyond a shadow of a doubt, that the instances are in-scope +import Data.Bifunctor () +import Data.Bifoldable () +import Data.Bitraversable () + +#ifndef CURRENT_PACKAGE_KEY +import Data.Version (showVersion) +import Paths_bifunctors (version) +#endif + +------------------------------------------------------------------------------- +-- Expanding type synonyms +------------------------------------------------------------------------------- + +applySubstitutionKind :: Map Name Kind -> Type -> Type +#if MIN_VERSION_template_haskell(2,8,0) +applySubstitutionKind = applySubstitution +#else +applySubstitutionKind _ t = t +#endif + +substNameWithKind :: Name -> Kind -> Type -> Type +substNameWithKind n k = applySubstitutionKind (Map.singleton n k) + +substNamesWithKindStar :: [Name] -> Type -> Type +substNamesWithKindStar ns t = foldr' (flip substNameWithKind starK) t ns + +------------------------------------------------------------------------------- +-- Type-specialized const functions +------------------------------------------------------------------------------- + +bimapConst :: p b d -> (a -> b) -> (c -> d) -> p a c -> p b d +bimapConst = const . const . const +{-# INLINE bimapConst #-} + +bifoldrConst :: c -> (a -> c -> c) -> (b -> c -> c) -> c -> p a b -> c +bifoldrConst = const . const . const . const +{-# INLINE bifoldrConst #-} + +bifoldMapConst :: m -> (a -> m) -> (b -> m) -> p a b -> m +bifoldMapConst = const . const . const +{-# INLINE bifoldMapConst #-} + +bitraverseConst :: f (t c d) -> (a -> f c) -> (b -> f d) -> t a b -> f (t c d) +bitraverseConst = const . const . const +{-# INLINE bitraverseConst #-} + +------------------------------------------------------------------------------- +-- StarKindStatus +------------------------------------------------------------------------------- + +-- | Whether a type is not of kind *, is of kind *, or is a kind variable. +data StarKindStatus = NotKindStar + | KindStar + | IsKindVar Name + deriving Eq + +-- | Does a Type have kind * or k (for some kind variable k)? +canRealizeKindStar :: Type -> StarKindStatus +canRealizeKindStar t + | hasKindStar t = KindStar + | otherwise = case t of +#if MIN_VERSION_template_haskell(2,8,0) + SigT _ (VarT k) -> IsKindVar k +#endif + _ -> NotKindStar + +-- | Returns 'Just' the kind variable 'Name' of a 'StarKindStatus' if it exists. +-- Otherwise, returns 'Nothing'. +starKindStatusToName :: StarKindStatus -> Maybe Name +starKindStatusToName (IsKindVar n) = Just n +starKindStatusToName _ = Nothing + +-- | Concat together all of the StarKindStatuses that are IsKindVar and extract +-- the kind variables' Names out. +catKindVarNames :: [StarKindStatus] -> [Name] +catKindVarNames = mapMaybe starKindStatusToName + +------------------------------------------------------------------------------- +-- Assorted utilities +------------------------------------------------------------------------------- + +-- filterByList, filterByLists, and partitionByList taken from GHC (BSD3-licensed) + +-- | 'filterByList' takes a list of Bools and a list of some elements and +-- filters out these elements for which the corresponding value in the list of +-- Bools is False. This function does not check whether the lists have equal +-- length. +filterByList :: [Bool] -> [a] -> [a] +filterByList (True:bs) (x:xs) = x : filterByList bs xs +filterByList (False:bs) (_:xs) = filterByList bs xs +filterByList _ _ = [] + +-- | 'filterByLists' takes a list of Bools and two lists as input, and +-- outputs a new list consisting of elements from the last two input lists. For +-- each Bool in the list, if it is 'True', then it takes an element from the +-- former list. If it is 'False', it takes an element from the latter list. +-- The elements taken correspond to the index of the Bool in its list. +-- For example: +-- +-- @ +-- filterByLists [True, False, True, False] \"abcd\" \"wxyz\" = \"axcz\" +-- @ +-- +-- This function does not check whether the lists have equal length. +filterByLists :: [Bool] -> [a] -> [a] -> [a] +filterByLists (True:bs) (x:xs) (_:ys) = x : filterByLists bs xs ys +filterByLists (False:bs) (_:xs) (y:ys) = y : filterByLists bs xs ys +filterByLists _ _ _ = [] + +-- | 'partitionByList' takes a list of Bools and a list of some elements and +-- partitions the list according to the list of Bools. Elements corresponding +-- to 'True' go to the left; elements corresponding to 'False' go to the right. +-- For example, @partitionByList [True, False, True] [1,2,3] == ([1,3], [2])@ +-- This function does not check whether the lists have equal +-- length. +partitionByList :: [Bool] -> [a] -> ([a], [a]) +partitionByList = go [] [] + where + go trues falses (True : bs) (x : xs) = go (x:trues) falses bs xs + go trues falses (False : bs) (x : xs) = go trues (x:falses) bs xs + go trues falses _ _ = (reverse trues, reverse falses) + +-- | Returns True if a Type has kind *. +hasKindStar :: Type -> Bool +hasKindStar VarT{} = True +#if MIN_VERSION_template_haskell(2,8,0) +hasKindStar (SigT _ StarT) = True +#else +hasKindStar (SigT _ StarK) = True +#endif +hasKindStar _ = False + +-- Returns True is a kind is equal to *, or if it is a kind variable. +isStarOrVar :: Kind -> Bool +#if MIN_VERSION_template_haskell(2,8,0) +isStarOrVar StarT = True +isStarOrVar VarT{} = True +#else +isStarOrVar StarK = True +#endif +isStarOrVar _ = False + +-- | @hasKindVarChain n kind@ Checks if @kind@ is of the form +-- k_0 -> k_1 -> ... -> k_(n-1), where k0, k1, ..., and k_(n-1) can be * or +-- kind variables. +hasKindVarChain :: Int -> Type -> Maybe [Name] +hasKindVarChain kindArrows t = + let uk = uncurryKind (tyKind t) + in if (length uk - 1 == kindArrows) && all isStarOrVar uk + then Just (freeVariables uk) + else Nothing + +-- | If a Type is a SigT, returns its kind signature. Otherwise, return *. +tyKind :: Type -> Kind +tyKind (SigT _ k) = k +tyKind _ = starK + +-- | A mapping of type variable Names to their map function Names. For example, in a +-- Bifunctor declaration, a TyVarMap might look like (a ~> f, b ~> g), where +-- a and b are the last two type variables of the datatype, and f and g are the two +-- functions which map their respective type variables. +type TyVarMap = Map Name Name + +thd3 :: (a, b, c) -> c +thd3 (_, _, c) = c + +unsnoc :: [a] -> Maybe ([a], a) +unsnoc [] = Nothing +unsnoc (x:xs) = case unsnoc xs of + Nothing -> Just ([], x) + Just (a,b) -> Just (x:a, b) + +-- | Generate a list of fresh names with a common prefix, and numbered suffixes. +newNameList :: String -> Int -> Q [Name] +newNameList prefix n = mapM (newName . (prefix ++) . show) [1..n] + +-- | Applies a typeclass constraint to a type. +applyClass :: Name -> Name -> Pred +#if MIN_VERSION_template_haskell(2,10,0) +applyClass con t = AppT (ConT con) (VarT t) +#else +applyClass con t = ClassP con [VarT t] +#endif + +-- | Checks to see if the last types in a data family instance can be safely eta- +-- reduced (i.e., dropped), given the other types. This checks for three conditions: +-- +-- (1) All of the dropped types are type variables +-- (2) All of the dropped types are distinct +-- (3) None of the remaining types mention any of the dropped types +canEtaReduce :: [Type] -> [Type] -> Bool +canEtaReduce remaining dropped = + all isTyVar dropped + && allDistinct droppedNames -- Make sure not to pass something of type [Type], since Type + -- didn't have an Ord instance until template-haskell-2.10.0.0 + && not (any (`mentionsName` droppedNames) remaining) + where + droppedNames :: [Name] + droppedNames = map varTToName dropped + +-- | Extract Just the Name from a type variable. If the argument Type is not a +-- type variable, return Nothing. +varTToName_maybe :: Type -> Maybe Name +varTToName_maybe (VarT n) = Just n +varTToName_maybe (SigT t _) = varTToName_maybe t +varTToName_maybe _ = Nothing + +-- | Extract the Name from a type variable. If the argument Type is not a +-- type variable, throw an error. +varTToName :: Type -> Name +varTToName = fromMaybe (error "Not a type variable!") . varTToName_maybe + +-- | Peel off a kind signature from a Type (if it has one). +unSigT :: Type -> Type +unSigT (SigT t _) = t +unSigT t = t + +-- | Is the given type a variable? +isTyVar :: Type -> Bool +isTyVar (VarT _) = True +isTyVar (SigT t _) = isTyVar t +isTyVar _ = False + +-- | Detect if a Name in a list of provided Names occurs as an argument to some +-- type family. This makes an effort to exclude /oversaturated/ arguments to +-- type families. For instance, if one declared the following type family: +-- +-- @ +-- type family F a :: Type -> Type +-- @ +-- +-- Then in the type @F a b@, we would consider @a@ to be an argument to @F@, +-- but not @b@. +isInTypeFamilyApp :: [Name] -> Type -> [Type] -> Q Bool +isInTypeFamilyApp names tyFun tyArgs = + case tyFun of + ConT tcName -> go tcName + _ -> return False + where + go :: Name -> Q Bool + go tcName = do + info <- reify tcName + case info of +#if MIN_VERSION_template_haskell(2,11,0) + FamilyI (OpenTypeFamilyD (TypeFamilyHead _ bndrs _ _)) _ + -> withinFirstArgs bndrs +#elif MIN_VERSION_template_haskell(2,7,0) + FamilyI (FamilyD TypeFam _ bndrs _) _ + -> withinFirstArgs bndrs +#else + TyConI (FamilyD TypeFam _ bndrs _) + -> withinFirstArgs bndrs +#endif + +#if MIN_VERSION_template_haskell(2,11,0) + FamilyI (ClosedTypeFamilyD (TypeFamilyHead _ bndrs _ _) _) _ + -> withinFirstArgs bndrs +#elif MIN_VERSION_template_haskell(2,9,0) + FamilyI (ClosedTypeFamilyD _ bndrs _ _) _ + -> withinFirstArgs bndrs +#endif + + _ -> return False + where + withinFirstArgs :: [a] -> Q Bool + withinFirstArgs bndrs = + let firstArgs = take (length bndrs) tyArgs + argFVs = freeVariables firstArgs + in return $ any (`elem` argFVs) names + +-- | Are all of the items in a list (which have an ordering) distinct? +-- +-- This uses Set (as opposed to nub) for better asymptotic time complexity. +allDistinct :: Ord a => [a] -> Bool +allDistinct = allDistinct' Set.empty + where + allDistinct' :: Ord a => Set a -> [a] -> Bool + allDistinct' uniqs (x:xs) + | x `Set.member` uniqs = False + | otherwise = allDistinct' (Set.insert x uniqs) xs + allDistinct' _ _ = True + +-- | Does the given type mention any of the Names in the list? +mentionsName :: Type -> [Name] -> Bool +mentionsName = go + where + go :: Type -> [Name] -> Bool + go (AppT t1 t2) names = go t1 names || go t2 names + go (SigT t _k) names = go t names +#if MIN_VERSION_template_haskell(2,8,0) + || go _k names +#endif + go (VarT n) names = n `elem` names + go _ _ = False + +-- | Does an instance predicate mention any of the Names in the list? +predMentionsName :: Pred -> [Name] -> Bool +#if MIN_VERSION_template_haskell(2,10,0) +predMentionsName = mentionsName +#else +predMentionsName (ClassP n tys) names = n `elem` names || any (`mentionsName` names) tys +predMentionsName (EqualP t1 t2) names = mentionsName t1 names || mentionsName t2 names +#endif + +-- | Construct a type via curried application. +applyTy :: Type -> [Type] -> Type +applyTy = List.foldl' AppT + +-- | Fully applies a type constructor to its type variables. +applyTyCon :: Name -> [Type] -> Type +applyTyCon = applyTy . ConT + +-- | Split an applied type into its individual components. For example, this: +-- +-- @ +-- Either Int Char +-- @ +-- +-- would split to this: +-- +-- @ +-- [Either, Int, Char] +-- @ +unapplyTy :: Type -> (Type, [Type]) +unapplyTy ty = go ty ty [] + where + go :: Type -> Type -> [Type] -> (Type, [Type]) + go _ (AppT ty1 ty2) args = go ty1 ty1 (ty2:args) + go origTy (SigT ty' _) args = go origTy ty' args +#if MIN_VERSION_template_haskell(2,11,0) + go origTy (InfixT ty1 n ty2) args = go origTy (ConT n `AppT` ty1 `AppT` ty2) args + go origTy (ParensT ty') args = go origTy ty' args +#endif + go origTy _ args = (origTy, args) + +-- | Split a type signature by the arrows on its spine. For example, this: +-- +-- @ +-- forall a b. (a ~ b) => (a -> b) -> Char -> () +-- @ +-- +-- would split to this: +-- +-- @ +-- (a ~ b, [a -> b, Char, ()]) +-- @ +uncurryTy :: Type -> (Cxt, [Type]) +uncurryTy (AppT (AppT ArrowT t1) t2) = + let (ctxt, tys) = uncurryTy t2 + in (ctxt, t1:tys) +uncurryTy (SigT t _) = uncurryTy t +uncurryTy (ForallT _ ctxt t) = + let (ctxt', tys) = uncurryTy t + in (ctxt ++ ctxt', tys) +uncurryTy t = ([], [t]) + +-- | Like uncurryType, except on a kind level. +uncurryKind :: Kind -> [Kind] +#if MIN_VERSION_template_haskell(2,8,0) +uncurryKind = snd . uncurryTy +#else +uncurryKind (ArrowK k1 k2) = k1:uncurryKind k2 +uncurryKind k = [k] +#endif + +------------------------------------------------------------------------------- +-- Manually quoted names +------------------------------------------------------------------------------- + +-- By manually generating these names we avoid needing to use the +-- TemplateHaskell language extension when compiling the bifunctors library. +-- This allows the library to be used in stage1 cross-compilers. + +bifunctorsPackageKey :: String +#ifdef CURRENT_PACKAGE_KEY +bifunctorsPackageKey = CURRENT_PACKAGE_KEY +#else +bifunctorsPackageKey = "bifunctors-" ++ showVersion version +#endif + +mkBifunctorsName_tc :: String -> String -> Name +mkBifunctorsName_tc = mkNameG_tc bifunctorsPackageKey + +mkBifunctorsName_v :: String -> String -> Name +mkBifunctorsName_v = mkNameG_v bifunctorsPackageKey + +bimapConstValName :: Name +bimapConstValName = mkBifunctorsName_v "Data.Bifunctor.TH.Internal" "bimapConst" + +bifoldrConstValName :: Name +bifoldrConstValName = mkBifunctorsName_v "Data.Bifunctor.TH.Internal" "bifoldrConst" + +bifoldMapConstValName :: Name +bifoldMapConstValName = mkBifunctorsName_v "Data.Bifunctor.TH.Internal" "bifoldMapConst" + +coerceValName :: Name +coerceValName = mkNameG_v "ghc-prim" "GHC.Prim" "coerce" + +bitraverseConstValName :: Name +bitraverseConstValName = mkBifunctorsName_v "Data.Bifunctor.TH.Internal" "bitraverseConst" + +wrapMonadDataName :: Name +wrapMonadDataName = mkNameG_d "base" "Control.Applicative" "WrapMonad" + +functorTypeName :: Name +functorTypeName = mkNameG_tc "base" "GHC.Base" "Functor" + +foldableTypeName :: Name +foldableTypeName = mkNameG_tc "base" "Data.Foldable" "Foldable" + +traversableTypeName :: Name +traversableTypeName = mkNameG_tc "base" "Data.Traversable" "Traversable" + +composeValName :: Name +composeValName = mkNameG_v "base" "GHC.Base" "." + +idValName :: Name +idValName = mkNameG_v "base" "GHC.Base" "id" + +errorValName :: Name +errorValName = mkNameG_v "base" "GHC.Err" "error" + +flipValName :: Name +flipValName = mkNameG_v "base" "GHC.Base" "flip" + +fmapValName :: Name +fmapValName = mkNameG_v "base" "GHC.Base" "fmap" + +foldrValName :: Name +foldrValName = mkNameG_v "base" "Data.Foldable" "foldr" + +foldMapValName :: Name +foldMapValName = mkNameG_v "base" "Data.Foldable" "foldMap" + +seqValName :: Name +seqValName = mkNameG_v "ghc-prim" "GHC.Prim" "seq" + +traverseValName :: Name +traverseValName = mkNameG_v "base" "Data.Traversable" "traverse" + +unwrapMonadValName :: Name +unwrapMonadValName = mkNameG_v "base" "Control.Applicative" "unwrapMonad" + +#if MIN_VERSION_base(4,8,0) +bifunctorTypeName :: Name +bifunctorTypeName = mkNameG_tc "base" "Data.Bifunctor" "Bifunctor" + +bimapValName :: Name +bimapValName = mkNameG_v "base" "Data.Bifunctor" "bimap" + +pureValName :: Name +pureValName = mkNameG_v "base" "GHC.Base" "pure" + +apValName :: Name +apValName = mkNameG_v "base" "GHC.Base" "<*>" + +liftA2ValName :: Name +liftA2ValName = mkNameG_v "base" "GHC.Base" "liftA2" + +mappendValName :: Name +mappendValName = mkNameG_v "base" "GHC.Base" "mappend" + +memptyValName :: Name +memptyValName = mkNameG_v "base" "GHC.Base" "mempty" +#else +bifunctorTypeName :: Name +bifunctorTypeName = mkBifunctorsName_tc "Data.Bifunctor" "Bifunctor" + +bimapValName :: Name +bimapValName = mkBifunctorsName_v "Data.Bifunctor" "bimap" + +pureValName :: Name +pureValName = mkNameG_v "base" "Control.Applicative" "pure" + +apValName :: Name +apValName = mkNameG_v "base" "Control.Applicative" "<*>" + +liftA2ValName :: Name +liftA2ValName = mkNameG_v "base" "Control.Applicative" "liftA2" + +mappendValName :: Name +mappendValName = mkNameG_v "base" "Data.Monoid" "mappend" + +memptyValName :: Name +memptyValName = mkNameG_v "base" "Data.Monoid" "mempty" +#endif + +#if MIN_VERSION_base(4,10,0) +bifoldableTypeName :: Name +bifoldableTypeName = mkNameG_tc "base" "Data.Bifoldable" "Bifoldable" + +bitraversableTypeName :: Name +bitraversableTypeName = mkNameG_tc "base" "Data.Bitraversable" "Bitraversable" + +bifoldrValName :: Name +bifoldrValName = mkNameG_v "base" "Data.Bifoldable" "bifoldr" + +bifoldMapValName :: Name +bifoldMapValName = mkNameG_v "base" "Data.Bifoldable" "bifoldMap" + +bitraverseValName :: Name +bitraverseValName = mkNameG_v "base" "Data.Bitraversable" "bitraverse" +#else +bifoldableTypeName :: Name +bifoldableTypeName = mkBifunctorsName_tc "Data.Bifoldable" "Bifoldable" + +bitraversableTypeName :: Name +bitraversableTypeName = mkBifunctorsName_tc "Data.Bitraversable" "Bitraversable" + +bifoldrValName :: Name +bifoldrValName = mkBifunctorsName_v "Data.Bifoldable" "bifoldr" + +bifoldMapValName :: Name +bifoldMapValName = mkBifunctorsName_v "Data.Bifoldable" "bifoldMap" + +bitraverseValName :: Name +bitraverseValName = mkBifunctorsName_v "Data.Bitraversable" "bitraverse" +#endif + +#if MIN_VERSION_base(4,11,0) +appEndoValName :: Name +appEndoValName = mkNameG_v "base" "Data.Semigroup.Internal" "appEndo" + +dualDataName :: Name +dualDataName = mkNameG_d "base" "Data.Semigroup.Internal" "Dual" + +endoDataName :: Name +endoDataName = mkNameG_d "base" "Data.Semigroup.Internal" "Endo" + +getDualValName :: Name +getDualValName = mkNameG_v "base" "Data.Semigroup.Internal" "getDual" +#else +appEndoValName :: Name +appEndoValName = mkNameG_v "base" "Data.Monoid" "appEndo" + +dualDataName :: Name +dualDataName = mkNameG_d "base" "Data.Monoid" "Dual" + +endoDataName :: Name +endoDataName = mkNameG_d "base" "Data.Monoid" "Endo" + +getDualValName :: Name +getDualValName = mkNameG_v "base" "Data.Monoid" "getDual" +#endif diff --git a/src/Data/Bifunctor/Tannen.hs b/src/Data/Bifunctor/Tannen.hs --- a/src/Data/Bifunctor/Tannen.hs +++ b/src/Data/Bifunctor/Tannen.hs @@ -1,211 +1,211 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE EmptyDataDecls #-} -{-# LANGUAGE FlexibleContexts #-} -{-# LANGUAGE StandaloneDeriving #-} -{-# LANGUAGE TypeFamilies #-} -{-# LANGUAGE TypeOperators #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif - -#if __GLASGOW_HASKELL__ >= 708 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif -#include "bifunctors-common.h" - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2008-2016 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bifunctor.Tannen - ( Tannen(..) - ) where - -import Control.Applicative - -import Control.Arrow as A -import Control.Category -import Control.Comonad - -import Data.Bifunctor as B -import Data.Bifunctor.Functor -import Data.Biapplicative -import Data.Bifoldable -import Data.Bitraversable - -#if __GLASGOW_HASKELL__ < 710 -import Data.Foldable -import Data.Monoid -import Data.Traversable -#endif - -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif - -#if LIFTED_FUNCTOR_CLASSES -import Data.Functor.Classes -#endif - -import Prelude hiding ((.),id) - --- | Compose a 'Functor' on the outside of a 'Bifunctor'. -newtype Tannen f p a b = Tannen { runTannen :: f (p a b) } - deriving ( Eq, Ord, Show, Read -#if __GLASGOW_HASKELL__ >= 702 - , Generic -#endif -#if __GLASGOW_HASKELL__ >= 708 - , Typeable -#endif - ) -#if __GLASGOW_HASKELL__ >= 702 -# if __GLASGOW_HASKELL__ >= 708 -deriving instance Functor f => Generic1 (Tannen f p a) -# else -data TannenMetaData -data TannenMetaCons -data TannenMetaSel - -instance Datatype TannenMetaData where - datatypeName _ = "Tannen" - moduleName _ = "Data.Bifunctor.Tannen" - -instance Constructor TannenMetaCons where - conName _ = "Tannen" - conIsRecord _ = True - -instance Selector TannenMetaSel where - selName _ = "runTannen" - -instance Functor f => Generic1 (Tannen f p a) where - type Rep1 (Tannen f p a) = D1 TannenMetaData (C1 TannenMetaCons - (S1 TannenMetaSel (f :.: Rec1 (p a)))) - from1 = M1 . M1 . M1 . Comp1 . fmap Rec1 . runTannen - to1 = Tannen . fmap unRec1 . unComp1 . unM1 . unM1 . unM1 -# endif -#endif - -#if LIFTED_FUNCTOR_CLASSES -instance (Eq1 f, Eq2 p, Eq a) => Eq1 (Tannen f p a) where - liftEq = liftEq2 (==) -instance (Eq1 f, Eq2 p) => Eq2 (Tannen f p) where - liftEq2 f g (Tannen x) (Tannen y) = liftEq (liftEq2 f g) x y - -instance (Ord1 f, Ord2 p, Ord a) => Ord1 (Tannen f p a) where - liftCompare = liftCompare2 compare -instance (Ord1 f, Ord2 p) => Ord2 (Tannen f p) where - liftCompare2 f g (Tannen x) (Tannen y) = liftCompare (liftCompare2 f g) x y - -instance (Read1 f, Read2 p, Read a) => Read1 (Tannen f p a) where - liftReadsPrec = liftReadsPrec2 readsPrec readList -instance (Read1 f, Read2 p) => Read2 (Tannen f p) where - liftReadsPrec2 rp1 rl1 rp2 rl2 p = readParen (p > 10) $ \s0 -> do - ("Tannen", s1) <- lex s0 - ("{", s2) <- lex s1 - ("runTannen", s3) <- lex s2 - (x, s4) <- liftReadsPrec (liftReadsPrec2 rp1 rl1 rp2 rl2) - (liftReadList2 rp1 rl1 rp2 rl2) 0 s3 - ("}", s5) <- lex s4 - return (Tannen x, s5) - -instance (Show1 f, Show2 p, Show a) => Show1 (Tannen f p a) where - liftShowsPrec = liftShowsPrec2 showsPrec showList -instance (Show1 f, Show2 p) => Show2 (Tannen f p) where - liftShowsPrec2 sp1 sl1 sp2 sl2 p (Tannen x) = showParen (p > 10) $ - showString "Tannen {runTannen = " - . liftShowsPrec (liftShowsPrec2 sp1 sl1 sp2 sl2) - (liftShowList2 sp1 sl1 sp2 sl2) 0 x - . showChar '}' -#endif - -instance Functor f => BifunctorFunctor (Tannen f) where - bifmap f (Tannen fp) = Tannen (fmap f fp) - -instance (Functor f, Monad f) => BifunctorMonad (Tannen f) where - bireturn = Tannen . return - bibind f (Tannen fp) = Tannen $ fp >>= runTannen . f - -instance Comonad f => BifunctorComonad (Tannen f) where - biextract = extract . runTannen - biextend f (Tannen fp) = Tannen (extend (f . Tannen) fp) - -instance (Functor f, Bifunctor p) => Bifunctor (Tannen f p) where - first f = Tannen . fmap (B.first f) . runTannen - {-# INLINE first #-} - second f = Tannen . fmap (B.second f) . runTannen - {-# INLINE second #-} - bimap f g = Tannen . fmap (bimap f g) . runTannen - {-# INLINE bimap #-} - -instance (Functor f, Bifunctor p) => Functor (Tannen f p a) where - fmap f = Tannen . fmap (B.second f) . runTannen - {-# INLINE fmap #-} - -instance (Applicative f, Biapplicative p) => Biapplicative (Tannen f p) where - bipure a b = Tannen (pure (bipure a b)) - {-# INLINE bipure #-} - - Tannen fg <<*>> Tannen xy = Tannen ((<<*>>) <$> fg <*> xy) - {-# INLINE (<<*>>) #-} - -instance (Foldable f, Bifoldable p) => Foldable (Tannen f p a) where - foldMap f = foldMap (bifoldMap (const mempty) f) . runTannen - {-# INLINE foldMap #-} - -instance (Foldable f, Bifoldable p) => Bifoldable (Tannen f p) where - bifoldMap f g = foldMap (bifoldMap f g) . runTannen - {-# INLINE bifoldMap #-} - -instance (Traversable f, Bitraversable p) => Traversable (Tannen f p a) where - traverse f = fmap Tannen . traverse (bitraverse pure f) . runTannen - {-# INLINE traverse #-} - -instance (Traversable f, Bitraversable p) => Bitraversable (Tannen f p) where - bitraverse f g = fmap Tannen . traverse (bitraverse f g) . runTannen - {-# INLINE bitraverse #-} - -instance (Applicative f, Category p) => Category (Tannen f p) where - id = Tannen $ pure id - Tannen fpbc . Tannen fpab = Tannen $ liftA2 (.) fpbc fpab - -instance (Applicative f, Arrow p) => Arrow (Tannen f p) where - arr f = Tannen $ pure $ arr f - first = Tannen . fmap A.first . runTannen - second = Tannen . fmap A.second . runTannen - Tannen ab *** Tannen cd = Tannen $ liftA2 (***) ab cd - Tannen ab &&& Tannen ac = Tannen $ liftA2 (&&&) ab ac - -instance (Applicative f, ArrowChoice p) => ArrowChoice (Tannen f p) where - left = Tannen . fmap left . runTannen - right = Tannen . fmap right . runTannen - Tannen ab +++ Tannen cd = Tannen $ liftA2 (+++) ab cd - Tannen ac ||| Tannen bc = Tannen $ liftA2 (|||) ac bc - -instance (Applicative f, ArrowLoop p) => ArrowLoop (Tannen f p) where - loop = Tannen . fmap loop . runTannen - -instance (Applicative f, ArrowZero p) => ArrowZero (Tannen f p) where - zeroArrow = Tannen $ pure zeroArrow - -instance (Applicative f, ArrowPlus p) => ArrowPlus (Tannen f p) where - Tannen f <+> Tannen g = Tannen (liftA2 (<+>) f g) - +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE TypeFamilies #-} +{-# LANGUAGE TypeOperators #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif + +#if __GLASGOW_HASKELL__ >= 708 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif +#include "bifunctors-common.h" + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2008-2016 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +---------------------------------------------------------------------------- +module Data.Bifunctor.Tannen + ( Tannen(..) + ) where + +import Control.Applicative + +import Control.Arrow as A +import Control.Category +import Control.Comonad + +import Data.Bifunctor as B +import Data.Bifunctor.Functor +import Data.Biapplicative +import Data.Bifoldable +import Data.Bitraversable + +#if __GLASGOW_HASKELL__ < 710 +import Data.Foldable +import Data.Monoid +import Data.Traversable +#endif + +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif + +#if LIFTED_FUNCTOR_CLASSES +import Data.Functor.Classes +#endif + +import Prelude hiding ((.),id) + +-- | Compose a 'Functor' on the outside of a 'Bifunctor'. +newtype Tannen f p a b = Tannen { runTannen :: f (p a b) } + deriving ( Eq, Ord, Show, Read +#if __GLASGOW_HASKELL__ >= 702 + , Generic +#endif +#if __GLASGOW_HASKELL__ >= 708 + , Typeable +#endif + ) +#if __GLASGOW_HASKELL__ >= 702 +# if __GLASGOW_HASKELL__ >= 708 +deriving instance Functor f => Generic1 (Tannen f p a) +# else +data TannenMetaData +data TannenMetaCons +data TannenMetaSel + +instance Datatype TannenMetaData where + datatypeName _ = "Tannen" + moduleName _ = "Data.Bifunctor.Tannen" + +instance Constructor TannenMetaCons where + conName _ = "Tannen" + conIsRecord _ = True + +instance Selector TannenMetaSel where + selName _ = "runTannen" + +instance Functor f => Generic1 (Tannen f p a) where + type Rep1 (Tannen f p a) = D1 TannenMetaData (C1 TannenMetaCons + (S1 TannenMetaSel (f :.: Rec1 (p a)))) + from1 = M1 . M1 . M1 . Comp1 . fmap Rec1 . runTannen + to1 = Tannen . fmap unRec1 . unComp1 . unM1 . unM1 . unM1 +# endif +#endif + +#if LIFTED_FUNCTOR_CLASSES +instance (Eq1 f, Eq2 p, Eq a) => Eq1 (Tannen f p a) where + liftEq = liftEq2 (==) +instance (Eq1 f, Eq2 p) => Eq2 (Tannen f p) where + liftEq2 f g (Tannen x) (Tannen y) = liftEq (liftEq2 f g) x y + +instance (Ord1 f, Ord2 p, Ord a) => Ord1 (Tannen f p a) where + liftCompare = liftCompare2 compare +instance (Ord1 f, Ord2 p) => Ord2 (Tannen f p) where + liftCompare2 f g (Tannen x) (Tannen y) = liftCompare (liftCompare2 f g) x y + +instance (Read1 f, Read2 p, Read a) => Read1 (Tannen f p a) where + liftReadsPrec = liftReadsPrec2 readsPrec readList +instance (Read1 f, Read2 p) => Read2 (Tannen f p) where + liftReadsPrec2 rp1 rl1 rp2 rl2 p = readParen (p > 10) $ \s0 -> do + ("Tannen", s1) <- lex s0 + ("{", s2) <- lex s1 + ("runTannen", s3) <- lex s2 + (x, s4) <- liftReadsPrec (liftReadsPrec2 rp1 rl1 rp2 rl2) + (liftReadList2 rp1 rl1 rp2 rl2) 0 s3 + ("}", s5) <- lex s4 + return (Tannen x, s5) + +instance (Show1 f, Show2 p, Show a) => Show1 (Tannen f p a) where + liftShowsPrec = liftShowsPrec2 showsPrec showList +instance (Show1 f, Show2 p) => Show2 (Tannen f p) where + liftShowsPrec2 sp1 sl1 sp2 sl2 p (Tannen x) = showParen (p > 10) $ + showString "Tannen {runTannen = " + . liftShowsPrec (liftShowsPrec2 sp1 sl1 sp2 sl2) + (liftShowList2 sp1 sl1 sp2 sl2) 0 x + . showChar '}' +#endif + +instance Functor f => BifunctorFunctor (Tannen f) where + bifmap f (Tannen fp) = Tannen (fmap f fp) + +instance (Functor f, Monad f) => BifunctorMonad (Tannen f) where + bireturn = Tannen . return + bibind f (Tannen fp) = Tannen $ fp >>= runTannen . f + +instance Comonad f => BifunctorComonad (Tannen f) where + biextract = extract . runTannen + biextend f (Tannen fp) = Tannen (extend (f . Tannen) fp) + +instance (Functor f, Bifunctor p) => Bifunctor (Tannen f p) where + first f = Tannen . fmap (B.first f) . runTannen + {-# INLINE first #-} + second f = Tannen . fmap (B.second f) . runTannen + {-# INLINE second #-} + bimap f g = Tannen . fmap (bimap f g) . runTannen + {-# INLINE bimap #-} + +instance (Functor f, Bifunctor p) => Functor (Tannen f p a) where + fmap f = Tannen . fmap (B.second f) . runTannen + {-# INLINE fmap #-} + +instance (Applicative f, Biapplicative p) => Biapplicative (Tannen f p) where + bipure a b = Tannen (pure (bipure a b)) + {-# INLINE bipure #-} + + Tannen fg <<*>> Tannen xy = Tannen ((<<*>>) <$> fg <*> xy) + {-# INLINE (<<*>>) #-} + +instance (Foldable f, Bifoldable p) => Foldable (Tannen f p a) where + foldMap f = foldMap (bifoldMap (const mempty) f) . runTannen + {-# INLINE foldMap #-} + +instance (Foldable f, Bifoldable p) => Bifoldable (Tannen f p) where + bifoldMap f g = foldMap (bifoldMap f g) . runTannen + {-# INLINE bifoldMap #-} + +instance (Traversable f, Bitraversable p) => Traversable (Tannen f p a) where + traverse f = fmap Tannen . traverse (bitraverse pure f) . runTannen + {-# INLINE traverse #-} + +instance (Traversable f, Bitraversable p) => Bitraversable (Tannen f p) where + bitraverse f g = fmap Tannen . traverse (bitraverse f g) . runTannen + {-# INLINE bitraverse #-} + +instance (Applicative f, Category p) => Category (Tannen f p) where + id = Tannen $ pure id + Tannen fpbc . Tannen fpab = Tannen $ liftA2 (.) fpbc fpab + +instance (Applicative f, Arrow p) => Arrow (Tannen f p) where + arr f = Tannen $ pure $ arr f + first = Tannen . fmap A.first . runTannen + second = Tannen . fmap A.second . runTannen + Tannen ab *** Tannen cd = Tannen $ liftA2 (***) ab cd + Tannen ab &&& Tannen ac = Tannen $ liftA2 (&&&) ab ac + +instance (Applicative f, ArrowChoice p) => ArrowChoice (Tannen f p) where + left = Tannen . fmap left . runTannen + right = Tannen . fmap right . runTannen + Tannen ab +++ Tannen cd = Tannen $ liftA2 (+++) ab cd + Tannen ac ||| Tannen bc = Tannen $ liftA2 (|||) ac bc + +instance (Applicative f, ArrowLoop p) => ArrowLoop (Tannen f p) where + loop = Tannen . fmap loop . runTannen + +instance (Applicative f, ArrowZero p) => ArrowZero (Tannen f p) where + zeroArrow = Tannen $ pure zeroArrow + +instance (Applicative f, ArrowPlus p) => ArrowPlus (Tannen f p) where + Tannen f <+> Tannen g = Tannen (liftA2 (<+>) f g) + diff --git a/src/Data/Bifunctor/Wrapped.hs b/src/Data/Bifunctor/Wrapped.hs --- a/src/Data/Bifunctor/Wrapped.hs +++ b/src/Data/Bifunctor/Wrapped.hs @@ -1,160 +1,160 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE EmptyDataDecls #-} -{-# LANGUAGE TypeFamilies #-} - -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE DeriveGeneric #-} -#endif - -#if __GLASGOW_HASKELL__ >= 706 -{-# LANGUAGE PolyKinds #-} -#endif - -#if __GLASGOW_HASKELL__ >= 708 -{-# LANGUAGE Safe #-} -#elif __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Trustworthy #-} -#endif -#include "bifunctors-common.h" - ------------------------------------------------------------------------------ --- | --- Copyright : (C) 2008-2016 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bifunctor.Wrapped - ( WrappedBifunctor(..) - ) where - -#if __GLASGOW_HASKELL__ < 710 -import Control.Applicative -#endif - -import Data.Biapplicative -import Data.Bifoldable -import Data.Bitraversable - -#if __GLASGOW_HASKELL__ < 710 -import Data.Foldable -import Data.Monoid -import Data.Traversable -#endif - -#if __GLASGOW_HASKELL__ >= 708 -import Data.Typeable -#endif - -#if __GLASGOW_HASKELL__ >= 702 -import GHC.Generics -#endif - -#if LIFTED_FUNCTOR_CLASSES -import Data.Functor.Classes -#endif - --- | Make a 'Functor' over the second argument of a 'Bifunctor'. -newtype WrappedBifunctor p a b = WrapBifunctor { unwrapBifunctor :: p a b } - deriving ( Eq, Ord, Show, Read -#if __GLASGOW_HASKELL__ >= 702 - , Generic -#endif -#if __GLASGOW_HASKELL__ >= 708 - , Generic1 - , Typeable -#endif - ) - -#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 708 -data WrappedBifunctorMetaData -data WrappedBifunctorMetaCons -data WrappedBifunctorMetaSel - -instance Datatype WrappedBifunctorMetaData where - datatypeName = const "WrappedBifunctor" - moduleName = const "Data.Bifunctor.Wrapped" - -instance Constructor WrappedBifunctorMetaCons where - conName = const "WrapBifunctor" - conIsRecord = const True - -instance Selector WrappedBifunctorMetaSel where - selName = const "unwrapBifunctor" - -instance Generic1 (WrappedBifunctor p a) where - type Rep1 (WrappedBifunctor p a) = D1 WrappedBifunctorMetaData - (C1 WrappedBifunctorMetaCons - (S1 WrappedBifunctorMetaSel (Rec1 (p a)))) - from1 = M1 . M1 . M1 . Rec1 . unwrapBifunctor - to1 = WrapBifunctor . unRec1 . unM1 . unM1 . unM1 -#endif - -#if LIFTED_FUNCTOR_CLASSES -instance (Eq2 p, Eq a) => Eq1 (WrappedBifunctor p a) where - liftEq = liftEq2 (==) -instance Eq2 p => Eq2 (WrappedBifunctor p) where - liftEq2 f g (WrapBifunctor x) (WrapBifunctor y) = liftEq2 f g x y - -instance (Ord2 p, Ord a) => Ord1 (WrappedBifunctor p a) where - liftCompare = liftCompare2 compare -instance Ord2 p => Ord2 (WrappedBifunctor p) where - liftCompare2 f g (WrapBifunctor x) (WrapBifunctor y) = liftCompare2 f g x y - -instance (Read2 p, Read a) => Read1 (WrappedBifunctor p a) where - liftReadsPrec = liftReadsPrec2 readsPrec readList -instance Read2 p => Read2 (WrappedBifunctor p) where - liftReadsPrec2 rp1 rl1 rp2 rl2 p = readParen (p > 10) $ \s0 -> do - ("WrapBifunctor", s1) <- lex s0 - ("{", s2) <- lex s1 - ("unwrapBifunctor", s3) <- lex s2 - (x, s4) <- liftReadsPrec2 rp1 rl1 rp2 rl2 0 s3 - ("}", s5) <- lex s4 - return (WrapBifunctor x, s5) - -instance (Show2 p, Show a) => Show1 (WrappedBifunctor p a) where - liftShowsPrec = liftShowsPrec2 showsPrec showList -instance Show2 p => Show2 (WrappedBifunctor p) where - liftShowsPrec2 sp1 sl1 sp2 sl2 p (WrapBifunctor x) = showParen (p > 10) $ - showString "WrapBifunctor {unwrapBifunctor = " - . liftShowsPrec2 sp1 sl1 sp2 sl2 0 x - . showChar '}' -#endif - -instance Bifunctor p => Bifunctor (WrappedBifunctor p) where - first f = WrapBifunctor . first f . unwrapBifunctor - {-# INLINE first #-} - second f = WrapBifunctor . second f . unwrapBifunctor - {-# INLINE second #-} - bimap f g = WrapBifunctor . bimap f g . unwrapBifunctor - {-# INLINE bimap #-} - -instance Bifunctor p => Functor (WrappedBifunctor p a) where - fmap f = WrapBifunctor . second f . unwrapBifunctor - {-# INLINE fmap #-} - -instance Biapplicative p => Biapplicative (WrappedBifunctor p) where - bipure a b = WrapBifunctor (bipure a b) - {-# INLINE bipure #-} - WrapBifunctor fg <<*>> WrapBifunctor xy = WrapBifunctor (fg <<*>> xy) - {-# INLINE (<<*>>) #-} - -instance Bifoldable p => Foldable (WrappedBifunctor p a) where - foldMap f = bifoldMap (const mempty) f . unwrapBifunctor - {-# INLINE foldMap #-} - -instance Bifoldable p => Bifoldable (WrappedBifunctor p) where - bifoldMap f g = bifoldMap f g . unwrapBifunctor - {-# INLINE bifoldMap #-} - -instance Bitraversable p => Traversable (WrappedBifunctor p a) where - traverse f = fmap WrapBifunctor . bitraverse pure f . unwrapBifunctor - {-# INLINE traverse #-} - -instance Bitraversable p => Bitraversable (WrappedBifunctor p) where - bitraverse f g = fmap WrapBifunctor . bitraverse f g . unwrapBifunctor - {-# INLINE bitraverse #-} +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE TypeFamilies #-} + +#if __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE DeriveGeneric #-} +#endif + +#if __GLASGOW_HASKELL__ >= 706 +{-# LANGUAGE PolyKinds #-} +#endif + +#if __GLASGOW_HASKELL__ >= 708 +{-# LANGUAGE Safe #-} +#elif __GLASGOW_HASKELL__ >= 702 +{-# LANGUAGE Trustworthy #-} +#endif +#include "bifunctors-common.h" + +----------------------------------------------------------------------------- +-- | +-- Copyright : (C) 2008-2016 Edward Kmett +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Edward Kmett +-- Stability : provisional +-- Portability : portable +-- +---------------------------------------------------------------------------- +module Data.Bifunctor.Wrapped + ( WrappedBifunctor(..) + ) where + +#if __GLASGOW_HASKELL__ < 710 +import Control.Applicative +#endif + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bitraversable + +#if __GLASGOW_HASKELL__ < 710 +import Data.Foldable +import Data.Monoid +import Data.Traversable +#endif + +#if __GLASGOW_HASKELL__ >= 708 +import Data.Typeable +#endif + +#if __GLASGOW_HASKELL__ >= 702 +import GHC.Generics +#endif + +#if LIFTED_FUNCTOR_CLASSES +import Data.Functor.Classes +#endif + +-- | Make a 'Functor' over the second argument of a 'Bifunctor'. +newtype WrappedBifunctor p a b = WrapBifunctor { unwrapBifunctor :: p a b } + deriving ( Eq, Ord, Show, Read +#if __GLASGOW_HASKELL__ >= 702 + , Generic +#endif +#if __GLASGOW_HASKELL__ >= 708 + , Generic1 + , Typeable +#endif + ) + +#if __GLASGOW_HASKELL__ >= 702 && __GLASGOW_HASKELL__ < 708 +data WrappedBifunctorMetaData +data WrappedBifunctorMetaCons +data WrappedBifunctorMetaSel + +instance Datatype WrappedBifunctorMetaData where + datatypeName = const "WrappedBifunctor" + moduleName = const "Data.Bifunctor.Wrapped" + +instance Constructor WrappedBifunctorMetaCons where + conName = const "WrapBifunctor" + conIsRecord = const True + +instance Selector WrappedBifunctorMetaSel where + selName = const "unwrapBifunctor" + +instance Generic1 (WrappedBifunctor p a) where + type Rep1 (WrappedBifunctor p a) = D1 WrappedBifunctorMetaData + (C1 WrappedBifunctorMetaCons + (S1 WrappedBifunctorMetaSel (Rec1 (p a)))) + from1 = M1 . M1 . M1 . Rec1 . unwrapBifunctor + to1 = WrapBifunctor . unRec1 . unM1 . unM1 . unM1 +#endif + +#if LIFTED_FUNCTOR_CLASSES +instance (Eq2 p, Eq a) => Eq1 (WrappedBifunctor p a) where + liftEq = liftEq2 (==) +instance Eq2 p => Eq2 (WrappedBifunctor p) where + liftEq2 f g (WrapBifunctor x) (WrapBifunctor y) = liftEq2 f g x y + +instance (Ord2 p, Ord a) => Ord1 (WrappedBifunctor p a) where + liftCompare = liftCompare2 compare +instance Ord2 p => Ord2 (WrappedBifunctor p) where + liftCompare2 f g (WrapBifunctor x) (WrapBifunctor y) = liftCompare2 f g x y + +instance (Read2 p, Read a) => Read1 (WrappedBifunctor p a) where + liftReadsPrec = liftReadsPrec2 readsPrec readList +instance Read2 p => Read2 (WrappedBifunctor p) where + liftReadsPrec2 rp1 rl1 rp2 rl2 p = readParen (p > 10) $ \s0 -> do + ("WrapBifunctor", s1) <- lex s0 + ("{", s2) <- lex s1 + ("unwrapBifunctor", s3) <- lex s2 + (x, s4) <- liftReadsPrec2 rp1 rl1 rp2 rl2 0 s3 + ("}", s5) <- lex s4 + return (WrapBifunctor x, s5) + +instance (Show2 p, Show a) => Show1 (WrappedBifunctor p a) where + liftShowsPrec = liftShowsPrec2 showsPrec showList +instance Show2 p => Show2 (WrappedBifunctor p) where + liftShowsPrec2 sp1 sl1 sp2 sl2 p (WrapBifunctor x) = showParen (p > 10) $ + showString "WrapBifunctor {unwrapBifunctor = " + . liftShowsPrec2 sp1 sl1 sp2 sl2 0 x + . showChar '}' +#endif + +instance Bifunctor p => Bifunctor (WrappedBifunctor p) where + first f = WrapBifunctor . first f . unwrapBifunctor + {-# INLINE first #-} + second f = WrapBifunctor . second f . unwrapBifunctor + {-# INLINE second #-} + bimap f g = WrapBifunctor . bimap f g . unwrapBifunctor + {-# INLINE bimap #-} + +instance Bifunctor p => Functor (WrappedBifunctor p a) where + fmap f = WrapBifunctor . second f . unwrapBifunctor + {-# INLINE fmap #-} + +instance Biapplicative p => Biapplicative (WrappedBifunctor p) where + bipure a b = WrapBifunctor (bipure a b) + {-# INLINE bipure #-} + WrapBifunctor fg <<*>> WrapBifunctor xy = WrapBifunctor (fg <<*>> xy) + {-# INLINE (<<*>>) #-} + +instance Bifoldable p => Foldable (WrappedBifunctor p a) where + foldMap f = bifoldMap (const mempty) f . unwrapBifunctor + {-# INLINE foldMap #-} + +instance Bifoldable p => Bifoldable (WrappedBifunctor p) where + bifoldMap f g = bifoldMap f g . unwrapBifunctor + {-# INLINE bifoldMap #-} + +instance Bitraversable p => Traversable (WrappedBifunctor p a) where + traverse f = fmap WrapBifunctor . bitraverse pure f . unwrapBifunctor + {-# INLINE traverse #-} + +instance Bitraversable p => Bitraversable (WrappedBifunctor p) where + bitraverse f g = fmap WrapBifunctor . bitraverse f g . unwrapBifunctor + {-# INLINE bitraverse #-} diff --git a/tests/BifunctorSpec.hs b/tests/BifunctorSpec.hs --- a/tests/BifunctorSpec.hs +++ b/tests/BifunctorSpec.hs @@ -1,408 +1,542 @@ -{-# LANGUAGE CPP #-} -{-# LANGUAGE EmptyDataDecls #-} -{-# LANGUAGE ExistentialQuantification #-} -{-# LANGUAGE FlexibleContexts #-} -{-# LANGUAGE GADTs #-} -{-# LANGUAGE GeneralizedNewtypeDeriving #-} -{-# LANGUAGE MagicHash #-} -{-# LANGUAGE RankNTypes #-} -{-# LANGUAGE TemplateHaskell #-} -{-# LANGUAGE TypeFamilies #-} -{-# LANGUAGE TypeOperators #-} -{-# LANGUAGE UndecidableInstances #-} -#if __GLASGOW_HASKELL__ >= 708 -{-# LANGUAGE EmptyCase #-} -{-# LANGUAGE RoleAnnotations #-} -#endif - -{-# OPTIONS_GHC -fno-warn-name-shadowing #-} -{-# OPTIONS_GHC -fno-warn-unused-matches #-} -#if __GLASGOW_HASKELL__ >= 800 -{-# OPTIONS_GHC -fno-warn-unused-foralls #-} -#endif - -{-| -Module: BifunctorSpec -Copyright: (C) 2008-2015 Edward Kmett, (C) 2015 Ryan Scott -License: BSD-style (see the file LICENSE) -Maintainer: Edward Kmett -Portability: Template Haskell - -@hspec@ tests for the "Data.Bifunctor.TH" module. --} -module BifunctorSpec where - -import Data.Bifunctor -import Data.Bifunctor.TH -import Data.Bifoldable -import Data.Bitraversable - -import Data.Char (chr) -import Data.Functor.Classes (Eq1, Show1) -import Data.Functor.Compose (Compose(..)) -import Data.Functor.Identity (Identity(..)) -import Data.Monoid - -import GHC.Exts (Int#) - -import Test.Hspec -import Test.Hspec.QuickCheck (prop) -import Test.QuickCheck (Arbitrary) - -#if !(MIN_VERSION_base(4,8,0)) -import Control.Applicative (Applicative(..)) -import Data.Foldable (Foldable) -import Data.Traversable (Traversable) -#endif - -------------------------------------------------------------------------------- - --- Adapted from the test cases from --- https://ghc.haskell.org/trac/ghc/attachment/ticket/2953/deriving-functor-tests.patch - --- Plain data types - -data Strange a b c - = T1 a b c - | T2 [a] [b] [c] -- lists - | T3 [[a]] [[b]] [[c]] -- nested lists - | T4 (c,(b,b),(c,c)) -- tuples - | T5 ([c],Strange a b c) -- tycons - -type IntFun a b = (b -> Int) -> a -data StrangeFunctions a b c - = T6 (a -> c) -- function types - | T7 (a -> (c,a)) -- functions and tuples - | T8 ((b -> a) -> c) -- continuation - | T9 (IntFun b c) -- type synonyms - -data StrangeGADT a b where - T10 :: Ord d => d -> StrangeGADT c d - T11 :: Int -> StrangeGADT e Int - T12 :: c ~ Int => c -> StrangeGADT f Int - T13 :: i ~ Int => Int -> StrangeGADT h i - T14 :: k ~ Int => k -> StrangeGADT j k - T15 :: (n ~ c, c ~ Int) => Int -> c -> StrangeGADT m n - -data NotPrimitivelyRecursive a b - = S1 (NotPrimitivelyRecursive (a,a) (b, a)) - | S2 a - | S3 b - -newtype OneTwoCompose f g a b = OneTwoCompose (f (g a b)) - deriving (Arbitrary, Eq, Show) - -newtype ComplexConstraint f g a b = ComplexConstraint (f Int Int (g a,a,b)) - -data Universal a b - = Universal (forall b. (b,[a])) - | Universal2 (forall f. Bifunctor f => f a b) - | Universal3 (forall a. Maybe a) -- reuse a - | NotReallyUniversal (forall b. a) - -data Existential a b - = forall a. ExistentialList [a] - | forall f. Bitraversable f => ExistentialFunctor (f a b) - | forall b. SneakyUseSameName (Maybe b) - -data IntHash a b - = IntHash Int# Int# - | IntHashTuple Int# a b (a, b, Int, IntHash Int (a, b, Int)) - -data IntHashFun a b - = IntHashFun ((((a -> Int#) -> b) -> Int#) -> a) - -data Empty1 a b -data Empty2 a b -#if __GLASGOW_HASKELL__ >= 708 -type role Empty2 nominal nominal -#endif - -data TyCon81 a b - = TyCon81a (forall c. c -> (forall d. a -> d) -> a) - | TyCon81b (Int -> forall c. c -> b) - -type family F :: * -> * -> * -type instance F = Either - -data TyCon82 a b = TyCon82 (F a b) - --- Data families - -data family StrangeFam x y z -data instance StrangeFam a b c - = T1Fam a b c - | T2Fam [a] [b] [c] -- lists - | T3Fam [[a]] [[b]] [[c]] -- nested lists - | T4Fam (c,(b,b),(c,c)) -- tuples - | T5Fam ([c],Strange a b c) -- tycons - -data family StrangeFunctionsFam x y z -data instance StrangeFunctionsFam a b c - = T6Fam (a -> c) -- function types - | T7Fam (a -> (c,a)) -- functions and tuples - | T8Fam ((b -> a) -> c) -- continuation - | T9Fam (IntFun b c) -- type synonyms - -data family StrangeGADTFam x y -data instance StrangeGADTFam a b where - T10Fam :: Ord d => d -> StrangeGADTFam c d - T11Fam :: Int -> StrangeGADTFam e Int - T12Fam :: c ~ Int => c -> StrangeGADTFam f Int - T13Fam :: i ~ Int => Int -> StrangeGADTFam h i - T14Fam :: k ~ Int => k -> StrangeGADTFam j k - T15Fam :: (n ~ c, c ~ Int) => Int -> c -> StrangeGADTFam m n - -data family NotPrimitivelyRecursiveFam x y -data instance NotPrimitivelyRecursiveFam a b - = S1Fam (NotPrimitivelyRecursive (a,a) (b, a)) - | S2Fam a - | S3Fam b - -data family OneTwoComposeFam (j :: * -> *) (k :: * -> * -> *) x y -newtype instance OneTwoComposeFam f g a b = OneTwoComposeFam (f (g a b)) - deriving (Arbitrary, Eq, Show) - -data family ComplexConstraintFam (j :: * -> * -> * -> *) (k :: * -> *) x y -newtype instance ComplexConstraintFam f g a b = ComplexConstraintFam (f Int Int (g a,a,b)) - -data family UniversalFam x y -data instance UniversalFam a b - = UniversalFam (forall b. (b,[a])) - | Universal2Fam (forall f. Bifunctor f => f a b) - | Universal3Fam (forall a. Maybe a) -- reuse a - | NotReallyUniversalFam (forall b. a) - -data family ExistentialFam x y -data instance ExistentialFam a b - = forall a. ExistentialListFam [a] - | forall f. Bitraversable f => ExistentialFunctorFam (f a b) - | forall b. SneakyUseSameNameFam (Maybe b) - -data family IntHashFam x y -data instance IntHashFam a b - = IntHashFam Int# Int# - | IntHashTupleFam Int# a b (a, b, Int, IntHashFam Int (a, b, Int)) - -data family IntHashFunFam x y -data instance IntHashFunFam a b - = IntHashFunFam ((((a -> Int#) -> b) -> Int#) -> a) - -data family TyFamily81 x y -data instance TyFamily81 a b - = TyFamily81a (forall c. c -> (forall d. a -> d) -> a) - | TyFamily81b (Int -> forall c. c -> b) - -data family TyFamily82 x y -data instance TyFamily82 a b = TyFamily82 (F a b) - -------------------------------------------------------------------------------- - --- Plain data types - -$(deriveBifunctor ''Strange) -$(deriveBifoldable ''Strange) -$(deriveBitraversable ''Strange) - -$(deriveBifunctor ''StrangeFunctions) -$(deriveBifoldable ''StrangeGADT) - -$(deriveBifunctor ''NotPrimitivelyRecursive) -$(deriveBifoldable ''NotPrimitivelyRecursive) -$(deriveBitraversable ''NotPrimitivelyRecursive) - -$(deriveBifunctor ''OneTwoCompose) -$(deriveBifoldable ''OneTwoCompose) -$(deriveBitraversable ''OneTwoCompose) - -instance (Bifunctor (f Int), Functor g) => - Bifunctor (ComplexConstraint f g) where - bimap = $(makeBimap ''ComplexConstraint) - -instance (Bifoldable (f Int), Foldable g) => - Bifoldable (ComplexConstraint f g) where - bifoldr = $(makeBifoldr ''ComplexConstraint) - bifoldMap = $(makeBifoldMap ''ComplexConstraint) - -bifoldlComplexConstraint - :: (Bifoldable (f Int), Foldable g) - => (c -> a -> c) -> (c -> b -> c) -> c -> ComplexConstraint f g a b -> c -bifoldlComplexConstraint = $(makeBifoldl ''ComplexConstraint) - -bifoldComplexConstraint - :: (Bifoldable (f Int), Foldable g, Monoid m) - => ComplexConstraint f g m m -> m -bifoldComplexConstraint = $(makeBifold ''ComplexConstraint) - -instance (Bitraversable (f Int), Traversable g) => - Bitraversable (ComplexConstraint f g) where - bitraverse = $(makeBitraverse ''ComplexConstraint) - -bisequenceAComplexConstraint - :: (Bitraversable (f Int), Traversable g, Applicative t) - => ComplexConstraint f g (t a) (t b) -> t (ComplexConstraint f g a b) -bisequenceAComplexConstraint = $(makeBisequenceA ''ComplexConstraint) - -$(deriveBifunctor ''Universal) - -$(deriveBifunctor ''Existential) -$(deriveBifoldable ''Existential) -$(deriveBitraversable ''Existential) - -$(deriveBifunctor ''IntHash) -$(deriveBifoldable ''IntHash) -$(deriveBitraversable ''IntHash) - -$(deriveBifunctor ''IntHashFun) - -$(deriveBifunctor ''Empty1) -$(deriveBifoldable ''Empty1) -$(deriveBitraversable ''Empty1) - --- Use EmptyCase here -$(deriveBifunctorOptions defaultOptions{emptyCaseBehavior = True} ''Empty2) -$(deriveBifoldableOptions defaultOptions{emptyCaseBehavior = True} ''Empty2) -$(deriveBitraversableOptions defaultOptions{emptyCaseBehavior = True} ''Empty2) - -$(deriveBifunctor ''TyCon81) - -$(deriveBifunctor ''TyCon82) -$(deriveBifoldable ''TyCon82) -$(deriveBitraversable ''TyCon82) - -#if MIN_VERSION_template_haskell(2,7,0) --- Data families - -$(deriveBifunctor 'T1Fam) -$(deriveBifoldable 'T2Fam) -$(deriveBitraversable 'T3Fam) - -$(deriveBifunctor 'T6Fam) -$(deriveBifoldable 'T10Fam) - -$(deriveBifunctor 'S1Fam) -$(deriveBifoldable 'S2Fam) -$(deriveBitraversable 'S3Fam) - -$(deriveBifunctor 'OneTwoComposeFam) -$(deriveBifoldable 'OneTwoComposeFam) -$(deriveBitraversable 'OneTwoComposeFam) - -instance (Bifunctor (f Int), Functor g) => - Bifunctor (ComplexConstraintFam f g) where - bimap = $(makeBimap 'ComplexConstraintFam) - -instance (Bifoldable (f Int), Foldable g) => - Bifoldable (ComplexConstraintFam f g) where - bifoldr = $(makeBifoldr 'ComplexConstraintFam) - bifoldMap = $(makeBifoldMap 'ComplexConstraintFam) - -bifoldlComplexConstraintFam - :: (Bifoldable (f Int), Foldable g) - => (c -> a -> c) -> (c -> b -> c) -> c -> ComplexConstraintFam f g a b -> c -bifoldlComplexConstraintFam = $(makeBifoldl 'ComplexConstraintFam) - -bifoldComplexConstraintFam - :: (Bifoldable (f Int), Foldable g, Monoid m) - => ComplexConstraintFam f g m m -> m -bifoldComplexConstraintFam = $(makeBifold 'ComplexConstraintFam) - -instance (Bitraversable (f Int), Traversable g) => - Bitraversable (ComplexConstraintFam f g) where - bitraverse = $(makeBitraverse 'ComplexConstraintFam) - -bisequenceAComplexConstraintFam - :: (Bitraversable (f Int), Traversable g, Applicative t) - => ComplexConstraintFam f g (t a) (t b) -> t (ComplexConstraintFam f g a b) -bisequenceAComplexConstraintFam = $(makeBisequenceA 'ComplexConstraintFam) - -$(deriveBifunctor 'UniversalFam) - -$(deriveBifunctor 'ExistentialListFam) -$(deriveBifoldable 'ExistentialFunctorFam) -$(deriveBitraversable 'SneakyUseSameNameFam) - -$(deriveBifunctor 'IntHashFam) -$(deriveBifoldable 'IntHashTupleFam) -$(deriveBitraversable 'IntHashFam) - -$(deriveBifunctor 'IntHashFunFam) - -$(deriveBifunctor 'TyFamily81a) - -$(deriveBifunctor 'TyFamily82) -$(deriveBifoldable 'TyFamily82) -$(deriveBitraversable 'TyFamily82) -#endif - -------------------------------------------------------------------------------- - -prop_BifunctorLaws :: (Bifunctor p, Eq (p a b), Eq (p c d), Show (p a b), Show (p c d)) - => (a -> c) -> (b -> d) -> p a b -> Expectation -prop_BifunctorLaws f g x = do - bimap id id x `shouldBe` x - first id x `shouldBe` x - second id x `shouldBe` x - bimap f g x `shouldBe` (first f . second g) x - -prop_BifunctorEx :: (Bifunctor p, Eq (p [Int] [Int]), Show (p [Int] [Int])) => p [Int] [Int] -> Expectation -prop_BifunctorEx = prop_BifunctorLaws reverse (++ [42]) - -prop_BifoldableLaws :: (Eq a, Eq b, Eq z, Show a, Show b, Show z, - Monoid a, Monoid b, Bifoldable p) - => (a -> b) -> (a -> b) - -> (a -> z -> z) -> (a -> z -> z) - -> z -> p a a -> Expectation -prop_BifoldableLaws f g h i z x = do - bifold x `shouldBe` bifoldMap id id x - bifoldMap f g x `shouldBe` bifoldr (mappend . f) (mappend . g) mempty x - bifoldr h i z x `shouldBe` appEndo (bifoldMap (Endo . h) (Endo . i) x) z - -prop_BifoldableEx :: Bifoldable p => p [Int] [Int] -> Expectation -prop_BifoldableEx = prop_BifoldableLaws reverse (++ [42]) ((+) . length) ((*) . length) 0 - -prop_BitraversableLaws :: (Applicative f, Applicative g, Bitraversable p, - Eq (g (p c c)), Eq (p a b), Eq (p d e), Eq1 f, - Show (g (p c c)), Show (p a b), Show (p d e), Show1 f) - => (a -> f c) -> (b -> f c) -> (c -> f d) -> (c -> f e) - -> (forall x. f x -> g x) -> p a b -> Expectation -prop_BitraversableLaws f g h i t x = do - bitraverse (t . f) (t . g) x `shouldBe` (t . bitraverse f g) x - bitraverse Identity Identity x `shouldBe` Identity x - (Compose . fmap (bitraverse h i) . bitraverse f g) x - `shouldBe` bitraverse (Compose . fmap h . f) (Compose . fmap i . g) x - -prop_BitraversableEx :: (Bitraversable p, - Eq (p Char Char), Eq (p [Char] [Char]), Eq (p [Int] [Int]), - Show (p Char Char), Show (p [Char] [Char]), Show (p [Int] [Int])) - => p [Int] [Int] -> Expectation -prop_BitraversableEx = prop_BitraversableLaws - (replicate 2 . map (chr . abs)) - (replicate 4 . map (chr . abs)) - (++ "hello") - (++ "world") - reverse - -------------------------------------------------------------------------------- - -main :: IO () -main = hspec spec - -spec :: Spec -spec = do - describe "OneTwoCompose Maybe Either [Int] [Int]" $ do - prop "satisfies the Bifunctor laws" - (prop_BifunctorEx :: OneTwoCompose Maybe Either [Int] [Int] -> Expectation) - prop "satisfies the Bifoldable laws" - (prop_BifoldableEx :: OneTwoCompose Maybe Either [Int] [Int] -> Expectation) - prop "satisfies the Bitraversable laws" - (prop_BitraversableEx :: OneTwoCompose Maybe Either [Int] [Int] -> Expectation) -#if MIN_VERSION_template_haskell(2,7,0) - describe "OneTwoComposeFam Maybe Either [Int] [Int]" $ do - prop "satisfies the Bifunctor laws" - (prop_BifunctorEx :: OneTwoComposeFam Maybe Either [Int] [Int] -> Expectation) - prop "satisfies the Bifoldable laws" - (prop_BifoldableEx :: OneTwoComposeFam Maybe Either [Int] [Int] -> Expectation) - prop "satisfies the Bitraversable laws" - (prop_BitraversableEx :: OneTwoComposeFam Maybe Either [Int] [Int] -> Expectation) -#endif +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveFoldable #-} +{-# LANGUAGE DeriveFunctor #-} +{-# LANGUAGE DeriveTraversable #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE ExistentialQuantification #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE GADTs #-} +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE MagicHash #-} +{-# LANGUAGE RankNTypes #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE TemplateHaskell #-} +{-# LANGUAGE TupleSections #-} +{-# LANGUAGE TypeFamilies #-} +{-# LANGUAGE TypeOperators #-} +{-# LANGUAGE UndecidableInstances #-} +#if __GLASGOW_HASKELL__ >= 708 +{-# LANGUAGE EmptyCase #-} +{-# LANGUAGE RoleAnnotations #-} +#endif + +{-# OPTIONS_GHC -fno-warn-name-shadowing #-} +{-# OPTIONS_GHC -fno-warn-unused-matches #-} +#if __GLASGOW_HASKELL__ >= 800 +{-# OPTIONS_GHC -fno-warn-unused-foralls #-} +#endif + +{-| +Module: BifunctorSpec +Copyright: (C) 2008-2015 Edward Kmett, (C) 2015 Ryan Scott +License: BSD-style (see the file LICENSE) +Maintainer: Edward Kmett +Portability: Template Haskell + +@hspec@ tests for the "Data.Bifunctor.TH" module. +-} +module BifunctorSpec where + +import Data.Bifunctor +import Data.Bifunctor.TH +import Data.Bifoldable +import Data.Bitraversable + +import Data.Char (chr) +import Data.Functor.Classes (Eq1, Show1) +import Data.Functor.Compose (Compose(..)) +import Data.Functor.Identity (Identity(..)) +import Data.Monoid + +import GHC.Exts (Int#) + +import Test.Hspec +import Test.Hspec.QuickCheck (prop) +import Test.QuickCheck (Arbitrary) + +#if !(MIN_VERSION_base(4,8,0)) +import Control.Applicative (Applicative(..)) +import Data.Foldable (Foldable(..)) +import Data.Traversable (Traversable(..)) +#endif + +------------------------------------------------------------------------------- + +-- Adapted from the test cases from +-- https://ghc.haskell.org/trac/ghc/attachment/ticket/2953/deriving-functor-tests.patch + +-- Plain data types + +data Strange a b c + = T1 a b c + | T2 [a] [b] [c] -- lists + | T3 [[a]] [[b]] [[c]] -- nested lists + | T4 (c,(b,b),(c,c)) -- tuples + | T5 ([c],Strange a b c) -- tycons + deriving (Functor, Foldable, Traversable) + +type IntFun a b = (b -> Int) -> a +data StrangeFunctions a b c + = T6 (a -> c) -- function types + | T7 (a -> (c,a)) -- functions and tuples + | T8 ((b -> a) -> c) -- continuation + | T9 (IntFun b c) -- type synonyms + deriving Functor + +data StrangeGADT a b where + T10 :: Ord d => d -> StrangeGADT c d + T11 :: Int -> StrangeGADT e Int + T12 :: c ~ Int => c -> StrangeGADT f Int + T13 :: i ~ Int => Int -> StrangeGADT h i + T14 :: k ~ Int => k -> StrangeGADT j k + T15 :: (n ~ c, c ~ Int) => Int -> c -> StrangeGADT m n +instance Foldable (StrangeGADT a) where + foldMap f (T10 x) = f x + foldMap f (T11 _) = mempty + foldMap f (T12 _) = mempty + foldMap f (T13 _) = mempty + foldMap f (T14 x) = f x + foldMap f (T15 _ _) = mempty + +data NotPrimitivelyRecursive a b + = S1 (NotPrimitivelyRecursive (a,a) (b, a)) + | S2 a + | S3 b + deriving (Functor, Foldable, Traversable) + +newtype OneTwoCompose f g a b = OneTwoCompose (f (g a b)) + deriving (Arbitrary, Eq, Foldable, Functor, Show, Traversable) + +newtype ComplexConstraint f g a b = ComplexConstraint (f Int Int (g a,a,b)) +instance (Bifunctor (f Int), Functor g) => + Functor (ComplexConstraint f g a) where + fmap f (ComplexConstraint x) = + ComplexConstraint (bimap id (\(ga,a,b) -> (ga,a,f b)) x) +instance (Bifoldable (f Int), Foldable g) => + Foldable (ComplexConstraint f g a) where + foldMap f (ComplexConstraint x) = + bifoldMap (const mempty) (\(_,_,b) -> f b) x +instance (Bitraversable (f Int), Traversable g) => + Traversable (ComplexConstraint f g a) where + traverse f (ComplexConstraint x) = + ComplexConstraint `fmap` bitraverse pure (\(ga,a,b) -> (ga,a,) `fmap` f b) x + +data Universal a b + = Universal (forall b. (b,[a])) + | Universal2 (forall f. Bifunctor f => f a b) + | Universal3 (forall a. Maybe a) -- reuse a + | NotReallyUniversal (forall b. a) +instance Functor (Universal a) where + fmap f (Universal x) = Universal x + fmap f (Universal2 x) = Universal2 (bimap id f x) + fmap f (Universal3 x) = Universal3 x + fmap f (NotReallyUniversal x) = NotReallyUniversal x + +data Existential a b + = forall a. ExistentialList [a] + | forall f. Bitraversable f => ExistentialFunctor (f a b) + | forall b. SneakyUseSameName (Maybe b) +instance Functor (Existential a) where + fmap f (ExistentialList x) = ExistentialList x + fmap f (ExistentialFunctor x) = ExistentialFunctor (bimap id f x) + fmap f (SneakyUseSameName x) = SneakyUseSameName x +instance Foldable (Existential a) where + foldMap f (ExistentialList _) = mempty + foldMap f (ExistentialFunctor x) = bifoldMap (const mempty) f x + foldMap f (SneakyUseSameName _) = mempty +instance Traversable (Existential a) where + traverse f (ExistentialList x) = pure $ ExistentialList x + traverse f (ExistentialFunctor x) = ExistentialFunctor `fmap` bitraverse pure f x + traverse f (SneakyUseSameName x) = pure $ SneakyUseSameName x + +data IntHash a b + = IntHash Int# Int# + | IntHashTuple Int# a b (a, b, Int, IntHash Int (a, b, Int)) + deriving (Functor, Foldable) +instance Traversable (IntHash a) where + traverse f (IntHash x y) = pure (IntHash x y) + traverse f (IntHashTuple x y z (a,b,c,d)) = + (\z' b' d' -> IntHashTuple x y z' (a,b',c,d')) + `fmap` f z + <*> f b + <*> traverse (\(m,n,o) -> fmap (\n' -> (m,n',o)) (f n)) d + +data IntHashFun a b + = IntHashFun ((((a -> Int#) -> b) -> Int#) -> a) + deriving Functor + +data Empty1 a b + deriving (Functor, Foldable, Traversable) + +data Empty2 a b + deriving (Functor, Foldable, Traversable) +#if __GLASGOW_HASKELL__ >= 708 +type role Empty2 nominal nominal +#endif + +data TyCon81 a b + = TyCon81a (forall c. c -> (forall d. a -> d) -> a) + | TyCon81b (Int -> forall c. c -> b) +instance Functor (TyCon81 a) where + fmap f (TyCon81a g) = TyCon81a g + fmap f (TyCon81b g) = TyCon81b (\x y -> f (g x y)) + +type family F :: * -> * -> * +type instance F = Either + +data TyCon82 a b = TyCon82 (F a b) + deriving (Functor, Foldable, Traversable) + +-- Data families + +data family StrangeFam x y z +data instance StrangeFam a b c + = T1Fam a b c + | T2Fam [a] [b] [c] -- lists + | T3Fam [[a]] [[b]] [[c]] -- nested lists + | T4Fam (c,(b,b),(c,c)) -- tuples + | T5Fam ([c],Strange a b c) -- tycons +#if __GLASGOW_HASKELL__ >= 708 + -- Unfortunately, pre-7.8 versions of GHC suffer from a bug that prevents + -- deriving Functor for data family instances. We could write all of the + -- derived instances by hand, but that amount of boilerplate makes me + -- nauseous. Instead, I elect to guard the derived instances with CPP. + deriving (Functor, Foldable, Traversable) +#endif + +data family StrangeFunctionsFam x y z +data instance StrangeFunctionsFam a b c + = T6Fam (a -> c) -- function types + | T7Fam (a -> (c,a)) -- functions and tuples + | T8Fam ((b -> a) -> c) -- continuation + | T9Fam (IntFun b c) -- type synonyms +#if __GLASGOW_HASKELL__ >= 708 + deriving Functor +#endif + +data family StrangeGADTFam x y +data instance StrangeGADTFam a b where + T10Fam :: Ord d => d -> StrangeGADTFam c d + T11Fam :: Int -> StrangeGADTFam e Int + T12Fam :: c ~ Int => c -> StrangeGADTFam f Int + T13Fam :: i ~ Int => Int -> StrangeGADTFam h i + T14Fam :: k ~ Int => k -> StrangeGADTFam j k + T15Fam :: (n ~ c, c ~ Int) => Int -> c -> StrangeGADTFam m n +instance Foldable (StrangeGADTFam a) where + foldMap f (T10Fam x) = f x + foldMap f (T11Fam _) = mempty + foldMap f (T12Fam _) = mempty + foldMap f (T13Fam _) = mempty + foldMap f (T14Fam x) = f x + foldMap f (T15Fam _ _) = mempty + +data family NotPrimitivelyRecursiveFam x y +data instance NotPrimitivelyRecursiveFam a b + = S1Fam (NotPrimitivelyRecursive (a,a) (b, a)) + | S2Fam a + | S3Fam b +#if __GLASGOW_HASKELL__ >= 708 + deriving (Functor, Foldable, Traversable) +#endif + +data family OneTwoComposeFam (j :: * -> *) (k :: * -> * -> *) x y +newtype instance OneTwoComposeFam f g a b = OneTwoComposeFam (f (g a b)) + deriving ( Arbitrary, Eq, Show +#if __GLASGOW_HASKELL__ >= 708 + , Functor, Foldable, Traversable +#endif + ) + +data family ComplexConstraintFam (j :: * -> * -> * -> *) (k :: * -> *) x y +newtype instance ComplexConstraintFam f g a b = ComplexConstraintFam (f Int Int (g a,a,b)) +instance (Bifunctor (f Int), Functor g) => + Functor (ComplexConstraintFam f g a) where + fmap f (ComplexConstraintFam x) = + ComplexConstraintFam (bimap id (\(ga,a,b) -> (ga,a,f b)) x) +instance (Bifoldable (f Int), Foldable g) => + Foldable (ComplexConstraintFam f g a) where + foldMap f (ComplexConstraintFam x) = + bifoldMap (const mempty) (\(_,_,b) -> f b) x +instance (Bitraversable (f Int), Traversable g) => + Traversable (ComplexConstraintFam f g a) where + traverse f (ComplexConstraintFam x) = + ComplexConstraintFam `fmap` bitraverse pure (\(ga,a,b) -> (ga,a,) `fmap` f b) x + +data family UniversalFam x y +data instance UniversalFam a b + = UniversalFam (forall b. (b,[a])) + | Universal2Fam (forall f. Bifunctor f => f a b) + | Universal3Fam (forall a. Maybe a) -- reuse a + | NotReallyUniversalFam (forall b. a) +instance Functor (UniversalFam a) where + fmap f (UniversalFam x) = UniversalFam x + fmap f (Universal2Fam x) = Universal2Fam (bimap id f x) + fmap f (Universal3Fam x) = Universal3Fam x + fmap f (NotReallyUniversalFam x) = NotReallyUniversalFam x + +data family ExistentialFam x y +data instance ExistentialFam a b + = forall a. ExistentialListFam [a] + | forall f. Bitraversable f => ExistentialFunctorFam (f a b) + | forall b. SneakyUseSameNameFam (Maybe b) +instance Functor (ExistentialFam a) where + fmap f (ExistentialListFam x) = ExistentialListFam x + fmap f (ExistentialFunctorFam x) = ExistentialFunctorFam (bimap id f x) + fmap f (SneakyUseSameNameFam x) = SneakyUseSameNameFam x +instance Foldable (ExistentialFam a) where + foldMap f (ExistentialListFam _) = mempty + foldMap f (ExistentialFunctorFam x) = bifoldMap (const mempty) f x + foldMap f (SneakyUseSameNameFam _) = mempty +instance Traversable (ExistentialFam a) where + traverse f (ExistentialListFam x) = pure $ ExistentialListFam x + traverse f (ExistentialFunctorFam x) = ExistentialFunctorFam `fmap` bitraverse pure f x + traverse f (SneakyUseSameNameFam x) = pure $ SneakyUseSameNameFam x + +data family IntHashFam x y +data instance IntHashFam a b + = IntHashFam Int# Int# + | IntHashTupleFam Int# a b (a, b, Int, IntHashFam Int (a, b, Int)) +#if __GLASGOW_HASKELL__ >= 708 + deriving (Functor, Foldable) +-- Old versions of GHC are unable to derive Traversable instances for data types +-- with fields of unlifted types, so write this one by hand. +instance Traversable (IntHashFam a) where + traverse f (IntHashFam x y) = pure (IntHashFam x y) + traverse f (IntHashTupleFam x y z (a,b,c,d)) = + (\z' b' d' -> IntHashTupleFam x y z' (a,b',c,d')) + `fmap` f z + <*> f b + <*> traverse (\(m,n,o) -> fmap (\n' -> (m,n',o)) (f n)) d +#endif + +data family IntHashFunFam x y +data instance IntHashFunFam a b + = IntHashFunFam ((((a -> Int#) -> b) -> Int#) -> a) +#if __GLASGOW_HASKELL__ >= 708 + deriving Functor +#endif + +data family TyFamily81 x y +data instance TyFamily81 a b + = TyFamily81a (forall c. c -> (forall d. a -> d) -> a) + | TyFamily81b (Int -> forall c. c -> b) +instance Functor (TyFamily81 a) where + fmap f (TyFamily81a g) = TyFamily81a g + fmap f (TyFamily81b g) = TyFamily81b (\x y -> f (g x y)) + +data family TyFamily82 x y +data instance TyFamily82 a b = TyFamily82 (F a b) +#if __GLASGOW_HASKELL__ >= 708 + deriving (Functor, Foldable, Traversable) +#endif + +------------------------------------------------------------------------------- + +-- Plain data types + +$(deriveBifunctor ''Strange) +$(deriveBifoldable ''Strange) +$(deriveBitraversable ''Strange) + +$(deriveBifunctor ''StrangeFunctions) +$(deriveBifoldable ''StrangeGADT) + +$(deriveBifunctor ''NotPrimitivelyRecursive) +$(deriveBifoldable ''NotPrimitivelyRecursive) +$(deriveBitraversable ''NotPrimitivelyRecursive) + +$(deriveBifunctor ''OneTwoCompose) +$(deriveBifoldable ''OneTwoCompose) +$(deriveBitraversable ''OneTwoCompose) + +instance (Bifunctor (f Int), Functor g) => + Bifunctor (ComplexConstraint f g) where + bimap = $(makeBimap ''ComplexConstraint) + +instance (Bifoldable (f Int), Foldable g) => + Bifoldable (ComplexConstraint f g) where + bifoldr = $(makeBifoldr ''ComplexConstraint) + bifoldMap = $(makeBifoldMap ''ComplexConstraint) + +bifoldlComplexConstraint + :: (Bifoldable (f Int), Foldable g) + => (c -> a -> c) -> (c -> b -> c) -> c -> ComplexConstraint f g a b -> c +bifoldlComplexConstraint = $(makeBifoldl ''ComplexConstraint) + +bifoldComplexConstraint + :: (Bifoldable (f Int), Foldable g, Monoid m) + => ComplexConstraint f g m m -> m +bifoldComplexConstraint = $(makeBifold ''ComplexConstraint) + +instance (Bitraversable (f Int), Traversable g) => + Bitraversable (ComplexConstraint f g) where + bitraverse = $(makeBitraverse ''ComplexConstraint) + +bisequenceAComplexConstraint + :: (Bitraversable (f Int), Traversable g, Applicative t) + => ComplexConstraint f g (t a) (t b) -> t (ComplexConstraint f g a b) +bisequenceAComplexConstraint = $(makeBisequenceA ''ComplexConstraint) + +$(deriveBifunctor ''Universal) + +$(deriveBifunctor ''Existential) +$(deriveBifoldable ''Existential) +$(deriveBitraversable ''Existential) + +$(deriveBifunctor ''IntHash) +$(deriveBifoldable ''IntHash) +$(deriveBitraversable ''IntHash) + +$(deriveBifunctor ''IntHashFun) + +$(deriveBifunctor ''Empty1) +$(deriveBifoldable ''Empty1) +$(deriveBitraversable ''Empty1) + +-- Use EmptyCase here +$(deriveBifunctorOptions defaultOptions{emptyCaseBehavior = True} ''Empty2) +$(deriveBifoldableOptions defaultOptions{emptyCaseBehavior = True} ''Empty2) +$(deriveBitraversableOptions defaultOptions{emptyCaseBehavior = True} ''Empty2) + +$(deriveBifunctor ''TyCon81) + +$(deriveBifunctor ''TyCon82) +$(deriveBifoldable ''TyCon82) +$(deriveBitraversable ''TyCon82) + +#if MIN_VERSION_template_haskell(2,7,0) +-- Data families + +$(deriveBifunctor 'T1Fam) +$(deriveBifoldable 'T2Fam) +$(deriveBitraversable 'T3Fam) + +$(deriveBifunctor 'T6Fam) +$(deriveBifoldable 'T10Fam) + +$(deriveBifunctor 'S1Fam) +$(deriveBifoldable 'S2Fam) +$(deriveBitraversable 'S3Fam) + +$(deriveBifunctor 'OneTwoComposeFam) +$(deriveBifoldable 'OneTwoComposeFam) +$(deriveBitraversable 'OneTwoComposeFam) + +instance (Bifunctor (f Int), Functor g) => + Bifunctor (ComplexConstraintFam f g) where + bimap = $(makeBimap 'ComplexConstraintFam) + +instance (Bifoldable (f Int), Foldable g) => + Bifoldable (ComplexConstraintFam f g) where + bifoldr = $(makeBifoldr 'ComplexConstraintFam) + bifoldMap = $(makeBifoldMap 'ComplexConstraintFam) + +bifoldlComplexConstraintFam + :: (Bifoldable (f Int), Foldable g) + => (c -> a -> c) -> (c -> b -> c) -> c -> ComplexConstraintFam f g a b -> c +bifoldlComplexConstraintFam = $(makeBifoldl 'ComplexConstraintFam) + +bifoldComplexConstraintFam + :: (Bifoldable (f Int), Foldable g, Monoid m) + => ComplexConstraintFam f g m m -> m +bifoldComplexConstraintFam = $(makeBifold 'ComplexConstraintFam) + +instance (Bitraversable (f Int), Traversable g) => + Bitraversable (ComplexConstraintFam f g) where + bitraverse = $(makeBitraverse 'ComplexConstraintFam) + +bisequenceAComplexConstraintFam + :: (Bitraversable (f Int), Traversable g, Applicative t) + => ComplexConstraintFam f g (t a) (t b) -> t (ComplexConstraintFam f g a b) +bisequenceAComplexConstraintFam = $(makeBisequenceA 'ComplexConstraintFam) + +$(deriveBifunctor 'UniversalFam) + +$(deriveBifunctor 'ExistentialListFam) +$(deriveBifoldable 'ExistentialFunctorFam) +$(deriveBitraversable 'SneakyUseSameNameFam) + +$(deriveBifunctor 'IntHashFam) +$(deriveBifoldable 'IntHashTupleFam) +$(deriveBitraversable 'IntHashFam) + +$(deriveBifunctor 'IntHashFunFam) + +$(deriveBifunctor 'TyFamily81a) + +$(deriveBifunctor 'TyFamily82) +$(deriveBifoldable 'TyFamily82) +$(deriveBitraversable 'TyFamily82) +#endif + +------------------------------------------------------------------------------- + +prop_BifunctorLaws :: (Bifunctor p, Eq (p a b), Eq (p c d), Show (p a b), Show (p c d)) + => (a -> c) -> (b -> d) -> p a b -> Expectation +prop_BifunctorLaws f g x = do + bimap id id x `shouldBe` x + first id x `shouldBe` x + second id x `shouldBe` x + bimap f g x `shouldBe` (first f . second g) x + +prop_BifunctorEx :: (Bifunctor p, Eq (p [Int] [Int]), Show (p [Int] [Int])) => p [Int] [Int] -> Expectation +prop_BifunctorEx = prop_BifunctorLaws reverse (++ [42]) + +prop_BifoldableLaws :: (Eq a, Eq b, Eq z, Show a, Show b, Show z, + Monoid a, Monoid b, Bifoldable p) + => (a -> b) -> (a -> b) + -> (a -> z -> z) -> (a -> z -> z) + -> z -> p a a -> Expectation +prop_BifoldableLaws f g h i z x = do + bifold x `shouldBe` bifoldMap id id x + bifoldMap f g x `shouldBe` bifoldr (mappend . f) (mappend . g) mempty x + bifoldr h i z x `shouldBe` appEndo (bifoldMap (Endo . h) (Endo . i) x) z + +prop_BifoldableEx :: Bifoldable p => p [Int] [Int] -> Expectation +prop_BifoldableEx = prop_BifoldableLaws reverse (++ [42]) ((+) . length) ((*) . length) 0 + +prop_BitraversableLaws :: (Applicative f, Applicative g, Bitraversable p, + Eq (g (p c c)), Eq (p a b), Eq (p d e), Eq1 f, + Show (g (p c c)), Show (p a b), Show (p d e), Show1 f) + => (a -> f c) -> (b -> f c) -> (c -> f d) -> (c -> f e) + -> (forall x. f x -> g x) -> p a b -> Expectation +prop_BitraversableLaws f g h i t x = do + bitraverse (t . f) (t . g) x `shouldBe` (t . bitraverse f g) x + bitraverse Identity Identity x `shouldBe` Identity x + (Compose . fmap (bitraverse h i) . bitraverse f g) x + `shouldBe` bitraverse (Compose . fmap h . f) (Compose . fmap i . g) x + +prop_BitraversableEx :: (Bitraversable p, + Eq (p Char Char), Eq (p [Char] [Char]), Eq (p [Int] [Int]), + Show (p Char Char), Show (p [Char] [Char]), Show (p [Int] [Int])) + => p [Int] [Int] -> Expectation +prop_BitraversableEx = prop_BitraversableLaws + (replicate 2 . map (chr . abs)) + (replicate 4 . map (chr . abs)) + (++ "hello") + (++ "world") + reverse + +------------------------------------------------------------------------------- + +main :: IO () +main = hspec spec + +spec :: Spec +spec = do + describe "OneTwoCompose Maybe Either [Int] [Int]" $ do + prop "satisfies the Bifunctor laws" + (prop_BifunctorEx :: OneTwoCompose Maybe Either [Int] [Int] -> Expectation) + prop "satisfies the Bifoldable laws" + (prop_BifoldableEx :: OneTwoCompose Maybe Either [Int] [Int] -> Expectation) + prop "satisfies the Bitraversable laws" + (prop_BitraversableEx :: OneTwoCompose Maybe Either [Int] [Int] -> Expectation) +#if MIN_VERSION_template_haskell(2,7,0) + describe "OneTwoComposeFam Maybe Either [Int] [Int]" $ do + prop "satisfies the Bifunctor laws" + (prop_BifunctorEx :: OneTwoComposeFam Maybe Either [Int] [Int] -> Expectation) + prop "satisfies the Bifoldable laws" + (prop_BifoldableEx :: OneTwoComposeFam Maybe Either [Int] [Int] -> Expectation) + prop "satisfies the Bitraversable laws" + (prop_BitraversableEx :: OneTwoComposeFam Maybe Either [Int] [Int] -> Expectation) +#endif diff --git a/tests/Spec.hs b/tests/Spec.hs --- a/tests/Spec.hs +++ b/tests/Spec.hs @@ -1,1 +1,1 @@ -{-# OPTIONS_GHC -F -pgmF hspec-discover #-} +{-# OPTIONS_GHC -F -pgmF hspec-discover #-} diff --git a/tests/T89Spec.hs b/tests/T89Spec.hs --- a/tests/T89Spec.hs +++ b/tests/T89Spec.hs @@ -1,21 +1,21 @@ -{-# LANGUAGE TemplateHaskell #-} - --- | A regression test for #89 which ensures that a TH-generated Bifoldable --- instance of a certain shape does not trigger -Wunused-matches warnings. -module T89Spec where - -import Data.Bifunctor.TH -import Test.Hspec - -data X = MkX -data Y a b = MkY a b -newtype XY a b = XY { getResp :: Either X (Y a b) } - -$(deriveBifoldable ''Y) -$(deriveBifoldable ''XY) - -main :: IO () -main = hspec spec - -spec :: Spec -spec = return () +{-# LANGUAGE TemplateHaskell #-} + +-- | A regression test for #89 which ensures that a TH-generated Bifoldable +-- instance of a certain shape does not trigger -Wunused-matches warnings. +module T89Spec where + +import Data.Bifunctor.TH +import Test.Hspec + +data X = MkX +data Y a b = MkY a b +newtype XY a b = XY { getResp :: Either X (Y a b) } + +$(deriveBifoldable ''Y) +$(deriveBifoldable ''XY) + +main :: IO () +main = hspec spec + +spec :: Spec +spec = return ()