diff --git a/.travis.yml b/.travis.yml deleted file mode 100644 --- a/.travis.yml +++ /dev/null @@ -1,1 +0,0 @@ -language: haskell diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown new file mode 100644 --- /dev/null +++ b/CHANGELOG.markdown @@ -0,0 +1,276 @@ +5.6.3 [2026.01.03] +------------------ +* Allow building with `template-haskell-2.24.*` (GHC 9.14). +* Remove unused dependencies. + +5.6.2 [2024.03.19] +------------------ +* Support building with `template-haskell-2.22.*` (GHC 9.10). + +5.6.1 [2023.03.13] +------------------ +* Provide instances for the `Swap` and `Assoc` type classes from the `assoc` + package. (These instances were previously defined in `assoc` itself, but they + have been migrated over to `bifunctors` in tandem with the `assoc-1.1` + release.) +* Only depend on `bifunctor-classes-compat` if building with GHC 8.0. + +5.6 [2023.03.12] +---------------- +* Drop support for GHC 7.10 and earlier. +* Move the `Data.Bifunctor`, `Data.Bifoldable`, and `Data.Bitraversable` + compatibility modules to the new `bifunctor-classes-compat` package. For + backwards compatibility, the `bifunctors` library re-exports + `Data.Bifoldable` and `Data.Bitraversable` modules from + `bifunctor-classes-compat` when building with GHC 8.0. + + If your library depends on `bifunctors` and compiles with pre-8.2 + versions of GHC, be warned that it may be possible to construct a + build plan involving a pre-`5.6` version of `bifunctors` where: + + * Some of the `Bifunctor` instances come from + `bifunctor-classes-compat`'s compatibility classes, and + * Other `Bifunctor` instances come from `bifunctors`'s compatibility classes. + + These compatibility classes are distinct, so this could lead to build errors + under certain conditions. Some possible ways to mitigate this risk include: + + * Drop support for GHC 8.0 and older in your library. + * Require `bifunctors >= 5.6` in your library. + * If neither of the options above are viable, then you can temporarily + define instances for the old compatibility classes from `bifunctors` like + so: + + ```hs + -- For Bifunctor instances + import qualified "bifunctor-classes-compat" Data.Bifunctor as BifunctorCompat + #if !MIN_VERSION_bifunctors(5,6,0) && !MIN_VERSION_base(4,8,0) + import qualified "bifunctors" Data.Bifunctor as Bifunctor + #endif + + instance BifunctorCompat.Bifunctor MyType where ... + + #if !MIN_VERSION_bifunctors(5,6,0) && !MIN_VERSION_base(4,8,0) + instance Bifunctor.Bifunctor MyType where ... + #endif + ``` + + ```hs + -- For Bifoldable and Bitraversable instances + import qualified "bifunctor-classes-compat" Data.Bifoldable as BifoldableCompat + import qualified "bifunctor-classes-compat" Data.Bitraversable as BitraversableCompat + #if !MIN_VERSION_bifunctors(5,6,0) && !MIN_VERSION_base(4,10,0) + import qualified "bifunctors" Data.Bifoldable as Bifoldable + import qualified "bifunctors" Data.Bitraversable as Bitraversable + #endif + + instance BifoldableCompat.Bifoldable MyType where ... + instance BitraversableCompat.Bitraversable MyType where ... + + #if !MIN_VERSION_bifunctors(5,6,0) && !MIN_VERSION_base(4,10,0) + instance Bifoldable.Bifoldable MyType where ... + instance Bitraversable.Bitraversable MyType where ... + #endif + ``` + + If your package does nothing but define instances of `Bifunctor` _et al._, + you may consider replacing your `bifunctors` dependency with + `bifunctor-classes-compat` to reduce your dependency footprint. If you do, + it is strongly recommended that you bump your package's major version number + so that your users are alerted to the details of the migration. +* Define a `Foldable1` instance for `Joker`, and define `Bifoldable1` instances + for `Biff`, `Clown`, `Flip`, `Join`, `Joker`, `Product`, `Tannen`, and + `WrappedBifunctor`. These instances were originally defined in the + `semigroupoids` library, and they have now been migrated to `bifunctors` as + a side effect of adapting to + [this Core Libraries Proposal](https://github.com/haskell/core-libraries-committee/issues/9), + which adds `Foldable1` and `Bifoldable1` to `base`. + +5.5.15 [2023.02.27] +------------------- +* Support `th-abstraction-0.5.*`. + +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 available 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 @@ -1,4 +1,4 @@ -Copyright 2008-2011 Edward Kmett +Copyright 2008-2016 Edward Kmett All rights reserved. @@ -12,10 +12,6 @@ 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. - -3. Neither the name of the author nor the names of his contributors - may be used to endorse or promote products derived from this software - without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED diff --git a/README.markdown b/README.markdown new file mode 100644 --- /dev/null +++ b/README.markdown @@ -0,0 +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 diff --git a/bifunctors.cabal b/bifunctors.cabal --- a/bifunctors.cabal +++ b/bifunctors.cabal @@ -1,37 +1,113 @@ +cabal-version: 1.24 name: bifunctors category: Data, Functors -version: 3.0 +version: 5.6.3 license: BSD3 -cabal-version: >= 1.6 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) 2008-2011 Edward A. Kmett -synopsis: Haskell 98 bifunctors -description: Haskell 98 bifunctors +copyright: Copyright (C) 2008-2016 Edward A. Kmett +synopsis: Bifunctors +description: Bifunctors. build-type: Simple -extra-source-files: .travis.yml +tested-with: 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 == 9.2.8 + , GHC == 9.4.8 + , GHC == 9.6.7 + , GHC == 9.8.4 + , GHC == 9.10.3 + , GHC == 9.12.2 + , GHC == 9.14.1 +extra-source-files: + CHANGELOG.markdown + README.markdown source-repository head type: git - location: git://github.com/ekmett/bifunctors.git + location: https://github.com/ekmett/bifunctors.git +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 build-depends: - base == 4.*, - semigroups >= 0.8.3.1 && < 0.9, - semigroupoids == 3.0.* + base >= 4.9 && < 5, + assoc >= 1.1 && < 1.2, + comonad >= 5.0.7 && < 6, + containers >= 0.5.7.1 && < 0.9, + template-haskell >= 2.11 && < 2.25, + th-abstraction >= 0.4.2.0 && < 0.8 + if !impl(ghc >= 8.2) + build-depends: + bifunctor-classes-compat >= 0.1 && < 0.2, + transformers-compat >= 0.6 && < 0.8 + + if flag(tagged) + build-depends: tagged >= 0.8.6 && < 1 + + if impl(ghc<8.1) + reexported-modules: + Data.Bifoldable + , Data.Bitraversable + + if !impl(ghc >= 9.6) + build-depends: foldable1-classes-compat >= 0.1 && < 0.2 + exposed-modules: - Data.Bifunctor - Data.Bifunctor.Apply - Data.Bifoldable - Data.Bitraversable - Data.Semigroup.Bifoldable - Data.Semigroup.Bitraversable + 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 + 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 diff --git a/src/Data/Biapplicative.hs b/src/Data/Biapplicative.hs new file mode 100644 --- /dev/null +++ b/src/Data/Biapplicative.hs @@ -0,0 +1,316 @@ +{-# LANGUAGE CPP #-} +{-# LANGUAGE GADTs #-} +{-# LANGUAGE RankNTypes #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# LANGUAGE Trustworthy #-} + +----------------------------------------------------------------------------- +-- | +-- 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(..) + , (<<$>>) + , (<<**>>) + , biliftA3 + , traverseBia + , sequenceBia + , traverseBiaWith + , module Data.Bifunctor + ) where + +import Control.Applicative +import Data.Bifunctor +import Data.Functor.Identity +import Data.Semigroup (Arg(..)) +import GHC.Exts (inline) + +#ifdef MIN_VERSION_tagged +import Data.Tagged +#endif + +infixl 4 <<$>>, <<*>>, <<*, *>>, <<**>> +(<<$>>) :: (a -> b) -> a -> b +(<<$>>) = id +{-# INLINE (<<$>>) #-} + +class Bifunctor p => Biapplicative p where + {-# MINIMAL bipure, ((<<*>>) | biliftA2 ) #-} + bipure :: a -> b -> p a b + + (<<*>>) :: p (a -> b) (c -> d) -> p a c -> p b d + (<<*>>) = biliftA2 id id + {-# INLINE (<<*>>) #-} + + -- | Lift binary functions + biliftA2 :: (a -> b -> c) -> (d -> e -> f) -> p a d -> p b e -> p c f + biliftA2 f g a b = bimap f g <<$>> 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 'Biapplicative' 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/Bifoldable.hs b/src/Data/Bifoldable.hs deleted file mode 100644 --- a/src/Data/Bifoldable.hs +++ /dev/null @@ -1,105 +0,0 @@ ------------------------------------------------------------------------------ --- | --- Module : Data.Bifoldable --- Copyright : (C) 2011 Edward Kmett, --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bifoldable - ( Bifoldable(..) - , bifoldr' - , bifoldrM - , bifoldl' - , bifoldlM - , bitraverse_ - , bifor_ - , bimapM_ - , biforM_ - , bisequenceA_ - , bisequence_ - , biList - , biconcat - , biconcatMap - , biany - , biall - ) where - -import Control.Applicative -import Data.Monoid - -class Bifoldable p where - bifold :: Monoid m => p m m -> m - bifold = bifoldMap id id - - bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> p a b -> m - bifoldMap f g = bifoldr (mappend . f) (mappend . g) mempty - - 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 - - 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 - -instance Bifoldable (,) where - bifoldMap f g (a, b) = f a `mappend` g b - -instance Bifoldable Either where - bifoldMap f _ (Left a) = f a - bifoldMap _ g (Right b) = g b - -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 - -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 - -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 - -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 - -bitraverse_ :: (Bifoldable t, Applicative f) => (a -> f c) -> (b -> f d) -> t a b -> f () -bitraverse_ f g = bifoldr ((*>) . f) ((*>) . g) (pure ()) - -bifor_ :: (Bifoldable t, Applicative f) => t a b -> (a -> f c) -> (b -> f d) -> f () -bifor_ t f g = bitraverse_ f g t - -bimapM_:: (Bifoldable t, Monad m) => (a -> m c) -> (b -> m d) -> t a b -> m () -bimapM_ f g = bifoldr ((>>) . f) ((>>) . g) (return ()) - -biforM_ :: (Bifoldable t, Monad m) => t a b -> (a -> m c) -> (b -> m d) -> m () -biforM_ t f g = bimapM_ f g t - -bisequenceA_ :: (Bifoldable t, Applicative f) => t (f a) (f b) -> f () -bisequenceA_ = bifoldr (*>) (*>) (pure ()) - -bisequence_ :: (Bifoldable t, Monad m) => t (m a) (m b) -> m () -bisequence_ = bifoldr (>>) (>>) (return ()) - -biList :: Bifoldable t => t a a -> [a] -biList = bifoldr (:) (:) [] - -biconcat :: Bifoldable t => t [a] [a] -> [a] -biconcat = bifold - -biconcatMap :: Bifoldable t => (a -> [c]) -> (b -> [c]) -> t a b -> [c] -biconcatMap = bifoldMap - -biany :: Bifoldable t => (a -> Bool) -> (b -> Bool) -> t a b -> Bool -biany p q = getAny . bifoldMap (Any . p) (Any . q) - -biall :: Bifoldable t => (a -> Bool) -> (b -> Bool) -> t a b -> Bool -biall p q = getAll . bifoldMap (All . p) (All . q) diff --git a/src/Data/Bifunctor.hs b/src/Data/Bifunctor.hs deleted file mode 100644 --- a/src/Data/Bifunctor.hs +++ /dev/null @@ -1,44 +0,0 @@ ------------------------------------------------------------------------------ --- | --- Module : Data.Bifunctor --- Copyright : (C) 2008-2011 Edward Kmett, --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bifunctor (Bifunctor(..)) where - -import Control.Applicative - --- | Minimal definition either 'bimap' or 'first' and 'second' -class Bifunctor p where - bimap :: (a -> b) -> (c -> d) -> p a c -> p b d - bimap f g = first f . second g - - first :: (a -> b) -> p a c -> p b c - first f = bimap f id - - second :: (b -> c) -> p a b -> p a c - second = bimap id - -instance Bifunctor (,) where - bimap f g (a, b) = (f a, g b) - -instance Bifunctor ((,,) x) where - bimap f g (x, a, b) = (x, f a, g b) - -instance Bifunctor ((,,,) x y) where - bimap f g (x, y, a, b) = (x, y, f a, g b) - -instance Bifunctor ((,,,,) x y z) where - bimap f g (x, y, z, a, b) = (x, y, z, f a, g b) - -instance Bifunctor Either where - bimap f _ (Left a) = Left (f a) - bimap _ g (Right b) = Right (g b) - -instance Bifunctor Const where - bimap f _ (Const a) = Const (f a) diff --git a/src/Data/Bifunctor/Apply.hs b/src/Data/Bifunctor/Apply.hs deleted file mode 100644 --- a/src/Data/Bifunctor/Apply.hs +++ /dev/null @@ -1,55 +0,0 @@ ------------------------------------------------------------------------------ --- | --- Module : Data.Bifunctor.Apply --- Copyright : (C) 2011 Edward Kmett, --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bifunctor.Apply ( - -- * Functors - -- * BiAppliable bifunctors - Biapply(..) - , (<<$>>) - , (<<..>>) - , bilift2 - , bilift3 - , module Data.Bifunctor - ) where - -import Data.Bifunctor - -infixl 4 <<$>>, <<.>>, <<., .>>, <<..>> - -(<<$>>) :: (a -> b) -> a -> b -(<<$>>) = id - -class Bifunctor p => Biapply p where - (<<.>>) :: p (a -> b) (c -> d) -> p a c -> p b d - - -- | a .> b = const id <$> a <.> b - (.>>) :: p a b -> p c d -> p c d - a .>> b = bimap (const id) (const id) <<$>> a <<.>> b - - -- | a <. b = const <$> a <.> b - (<<.) :: p a b -> p c d -> p a b - a <<. b = bimap const const <<$>> a <<.>> b - -(<<..>>) :: Biapply p => p a c -> p (a -> b) (c -> d) -> p b d -(<<..>>) = bilift2 (flip id) (flip id) - --- | Lift binary functions -bilift2 :: Biapply w => (a -> b -> c) -> (d -> e -> f) -> w a d -> w b e -> w c f -bilift2 f g a b = bimap f g <<$>> a <<.>> b -{-# INLINE bilift2 #-} - --- | Lift ternary functions -bilift3 :: Biapply w => (a -> b -> c -> d) -> (e -> f -> g -> h) -> w a e -> w b f -> w c g -> w d h -bilift3 f g a b c = bimap f g <<$>> a <<.>> b <<.>> c -{-# INLINE bilift3 #-} - -instance Biapply (,) where - (f, g) <<.>> (a, b) = (f a, g b) diff --git a/src/Data/Bifunctor/Biap.hs b/src/Data/Bifunctor/Biap.hs new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Biap.hs @@ -0,0 +1,116 @@ +{-# LANGUAGE CPP #-} +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE DeriveTraversable #-} +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# LANGUAGE TypeFamilies #-} +-- This module uses GND +{-# LANGUAGE Trustworthy #-} + +----------------------------------------------------------------------------- +-- | +-- 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 +import qualified Data.Semigroup as S +import GHC.Generics + +-- | 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 + , Generic + , Generic1 + , Monad + , Fail.MonadFail + , MonadPlus + , Eq1 + , Ord1 + , Bifunctor + , Biapplicative + , Bifoldable + , Eq2 + , Ord2 + ) + +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) => 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) diff --git a/src/Data/Bifunctor/Biff.hs b/src/Data/Bifunctor/Biff.hs new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Biff.hs @@ -0,0 +1,110 @@ +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE TypeFamilies #-} +{-# LANGUAGE TypeOperators #-} + +----------------------------------------------------------------------------- +-- | +-- 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 + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bifoldable1 (Bifoldable1(..)) +import Data.Bifunctor.Swap (Swap (..)) +import Data.Bitraversable +import Data.Foldable1 (Foldable1(..)) +import Data.Functor.Classes +import GHC.Generics + +-- | 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, Generic) +deriving instance Functor (p (f a)) => Generic1 (Biff p f g a) + +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 '}' + +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 (Bifoldable1 p, Foldable1 f, Foldable1 g) => Bifoldable1 (Biff p f g) where + bifoldMap1 f g = bifoldMap1 (foldMap1 f) (foldMap1 g) . runBiff + {-# INLINE bifoldMap1 #-} + +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 #-} + +-- | @since 5.6.1 +instance (f ~ g, Functor f, Swap p) => Swap (Biff p f g) where + swap = Biff . swap . runBiff diff --git a/src/Data/Bifunctor/Clown.hs b/src/Data/Bifunctor/Clown.hs new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Clown.hs @@ -0,0 +1,122 @@ +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE TypeFamilies #-} + +----------------------------------------------------------------------------- +-- | +-- 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 + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bifoldable1 (Bifoldable1(..)) +import Data.Bitraversable +import Data.Foldable1 (Foldable1(..)) +import Data.Functor.Classes +import GHC.Generics + +-- | 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, Generic, Generic1) + +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) + +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 Foldable1 f => Bifoldable1 (Clown f) where + bifoldMap1 f _ = foldMap1 f . runClown + {-# INLINE bifoldMap1 #-} + +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 new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Fix.hs @@ -0,0 +1,77 @@ +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE UndecidableInstances #-} + +----------------------------------------------------------------------------- +-- | +-- 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 + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bitraversable +import Data.Functor.Classes +import GHC.Generics + +-- | 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 Generic + +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) + +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 '}' + +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 new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Flip.hs @@ -0,0 +1,112 @@ +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE Safe #-} + +----------------------------------------------------------------------------- +-- | +-- 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 + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bifoldable1 (Bifoldable1(..)) +import Data.Bifunctor.Functor +import Data.Bifunctor.Swap (Swap (..)) +import Data.Bifunctor.Assoc (Assoc (..)) +import Data.Bitraversable +import Data.Functor.Classes +import GHC.Generics + +-- | Make a 'Bifunctor' flipping the arguments of a 'Bifunctor'. +newtype Flip p a b = Flip { runFlip :: p b a } + deriving (Eq, Ord, Show, Read, Generic) + +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 '}' + +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 Bifoldable1 p => Bifoldable1 (Flip p) where + bifoldMap1 f g = bifoldMap1 g f . runFlip + {-# INLINE bifoldMap1 #-} + +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) + +-- | @since 5.6.1 +instance Assoc p => Assoc (Flip p) where + assoc = Flip . first Flip . unassoc . second runFlip . runFlip + unassoc = Flip . second Flip . assoc . first runFlip . runFlip + +-- | @since 5.6.1 +instance Swap p => Swap (Flip p) where + swap = Flip . swap . runFlip diff --git a/src/Data/Bifunctor/Functor.hs b/src/Data/Bifunctor/Functor.hs new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Functor.hs @@ -0,0 +1,44 @@ +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE RankNTypes #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE TypeOperators #-} + +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 + {-# MINIMAL bireturn, (bibind | bijoin) #-} + +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 + {-# MINIMAL biextract, (biextend | biduplicate) #-} + +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 new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Join.hs @@ -0,0 +1,86 @@ +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE UndecidableInstances #-} + +----------------------------------------------------------------------------- +-- | +-- 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 + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bifoldable1 (Bifoldable1(..)) +import Data.Bitraversable +import Data.Foldable1 (Foldable1(..)) +import Data.Functor.Classes +import GHC.Generics + +-- | Make a 'Functor' over both arguments of a 'Bifunctor'. +newtype Join p a = Join { runJoin :: p a a } + deriving Generic + +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) + +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 '}' + +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 Bifoldable1 p => Foldable1 (Join p) where + foldMap1 f (Join a) = bifoldMap1 f f a + {-# INLINE foldMap1 #-} + +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 new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Joker.hs @@ -0,0 +1,126 @@ +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE TypeFamilies #-} + +----------------------------------------------------------------------------- +-- | +-- 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 + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bifoldable1 (Bifoldable1(..)) +import Data.Bitraversable +import Data.Foldable1 (Foldable1(..)) +import Data.Functor.Classes +import GHC.Generics + +-- | 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, Generic, Generic1) + +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) + +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 Foldable1 g => Bifoldable1 (Joker g) where + bifoldMap1 _ g = foldMap1 g . runJoker + {-# INLINE bifoldMap1 #-} + +instance Foldable g => Foldable (Joker g a) where + foldMap g = foldMap g . runJoker + {-# INLINE foldMap #-} + +instance Foldable1 g => Foldable1 (Joker g a) where + foldMap1 g = foldMap1 g . runJoker + {-# INLINE foldMap1 #-} + +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 new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Product.hs @@ -0,0 +1,138 @@ +{-# LANGUAGE DeriveFoldable #-} +{-# LANGUAGE DeriveFunctor #-} +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE DeriveTraversable #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE TypeFamilies #-} + +----------------------------------------------------------------------------- +-- | +-- 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.Bifoldable1 (Bifoldable1(..)) +import Data.Bifunctor.Functor +import Data.Bifunctor.Swap (Swap (..)) +import Data.Bitraversable +import Data.Functor.Classes +import qualified Data.Semigroup as S +import GHC.Generics + +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, Generic, Generic1) +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) + +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 + +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 (Bifoldable1 f, Bifoldable1 g) => Bifoldable1 (Product f g) where + bifoldMap1 f g (Pair x y) = bifoldMap1 f g x S.<> bifoldMap1 f g y + {-# INLINE bifoldMap1 #-} + +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') + +-- | @since 5.6.1 +instance (Swap p, Swap q) => Swap (Product p q) where + swap (Pair p q) = Pair (swap p) (swap q) diff --git a/src/Data/Bifunctor/Sum.hs b/src/Data/Bifunctor/Sum.hs new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Sum.hs @@ -0,0 +1,89 @@ +{-# LANGUAGE DeriveFoldable #-} +{-# LANGUAGE DeriveFunctor #-} +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE DeriveTraversable #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE TypeFamilies #-} + +module Data.Bifunctor.Sum where + +import Data.Bifunctor +import Data.Bifunctor.Functor +import Data.Bifunctor.Swap (Swap (..)) +import Data.Bifoldable +import Data.Bitraversable +import Data.Functor.Classes +import GHC.Generics + +data Sum p q a b = L2 (p a b) | R2 (q a b) + deriving (Eq, Ord, Show, Read, Generic, Generic1) +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) + +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 + +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 + +-- | @since 5.6.1 +instance (Swap p, Swap q) => Swap (Sum p q) where + swap (L2 p) = L2 (swap p) + swap (R2 q) = R2 (swap q) diff --git a/src/Data/Bifunctor/TH.hs b/src/Data/Bifunctor/TH.hs new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/TH.hs @@ -0,0 +1,1308 @@ +{-# LANGUAGE CPP #-} +{-# LANGUAGE BangPatterns #-} +{-# LANGUAGE PatternGuards #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# LANGUAGE Unsafe #-} +----------------------------------------------------------------------------- +-- | +-- 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 as 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. + } 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 + roles <- reifyRoles _parentName + case () of + _ | Just (rs, PhantomR) <- unsnoc roles + , Just (_, PhantomR) <- unsnoc rs + -> biFunPhantom z value + + | null cons && emptyCaseBehavior opts + -> biFunEmptyCase biFun z value + + | null cons + -> biFunNoCons biFun z value + + | otherwise + -> caseE (varE value) + (map (makeBiFunForCon biFun z tvMap) cons) + + 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 + +-- | 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 <- + case variant of + Datatype -> return False + Newtype -> return False + DataInstance -> return True + NewtypeInstance -> return True +#if MIN_VERSION_th_abstraction(0,5,0) + Datatype.TypeData -> typeDataError tyConName +#endif + + let 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 appeared 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 + +typeDataError :: Name -> Q a +typeDataError dataName = fail + . showString "Cannot derive instance for ‘" + . showString (nameBase dataName) + . showString "‘, which is a ‘type data‘ declaration" + $ "" + +------------------------------------------------------------------------------- +-- 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 + | UnboxedTupleT len <- f + -> tuple $ Unboxed len + | 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) + go_kind = go + + 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" + lamE [varP n] $ lam (VarE n) + +-- 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" + lamE [varP n1, varP n2] $ lam (VarE n1) (VarE n2) + +-- "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 + -- indices 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 + | Unboxed Int + +-- "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 + Unboxed len -> unboxedTupleDataName len + 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 new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/TH/Internal.hs @@ -0,0 +1,448 @@ +{-# LANGUAGE TemplateHaskellQuotes #-} +{-# LANGUAGE Unsafe #-} + +{-| +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 Control.Applicative +import Data.Bifunctor (Bifunctor(..)) +import Data.Bifoldable (Bifoldable(..)) +import Data.Bitraversable (Bitraversable(..)) +import Data.Coerce (coerce) +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 Data.Monoid (Dual(..), Endo(..)) +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 + +------------------------------------------------------------------------------- +-- Expanding type synonyms +------------------------------------------------------------------------------- + +applySubstitutionKind :: Map Name Kind -> Type -> Type +applySubstitutionKind = applySubstitution + +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 + SigT _ (VarT k) -> IsKindVar k + _ -> 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 +hasKindStar (SigT _ StarT) = True +hasKindStar _ = False + +-- Returns True is a kind is equal to *, or if it is a kind variable. +isStarOrVar :: Kind -> Bool +isStarOrVar StarT = True +isStarOrVar VarT{} = True +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 +applyClass con t = AppT (ConT con) (VarT t) + +-- | 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 + FamilyI (OpenTypeFamilyD (TypeFamilyHead _ bndrs _ _)) _ + -> withinFirstArgs bndrs + FamilyI (ClosedTypeFamilyD (TypeFamilyHead _ bndrs _ _) _) _ + -> withinFirstArgs bndrs + _ -> 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 || go k names + 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 +predMentionsName = mentionsName + +-- | 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 + 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 + 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] +uncurryKind = snd . uncurryTy + +------------------------------------------------------------------------------- +-- Quoted names +------------------------------------------------------------------------------- + +bimapConstValName :: Name +bimapConstValName = 'bimapConst + +bifoldrConstValName :: Name +bifoldrConstValName = 'bifoldrConst + +bifoldMapConstValName :: Name +bifoldMapConstValName = 'bifoldMapConst + +coerceValName :: Name +coerceValName = 'coerce + +bitraverseConstValName :: Name +bitraverseConstValName = 'bitraverseConst + +wrapMonadDataName :: Name +wrapMonadDataName = 'WrapMonad + +functorTypeName :: Name +functorTypeName = ''Functor + +foldableTypeName :: Name +foldableTypeName = ''Foldable + +traversableTypeName :: Name +traversableTypeName = ''Traversable + +composeValName :: Name +composeValName = '(.) + +idValName :: Name +idValName = 'id + +errorValName :: Name +errorValName = 'error + +flipValName :: Name +flipValName = 'flip + +fmapValName :: Name +fmapValName = 'fmap + +foldrValName :: Name +foldrValName = 'foldr + +foldMapValName :: Name +foldMapValName = 'foldMap + +seqValName :: Name +seqValName = 'seq + +traverseValName :: Name +traverseValName = 'traverse + +unwrapMonadValName :: Name +unwrapMonadValName = 'unwrapMonad + +bifunctorTypeName :: Name +bifunctorTypeName = ''Bifunctor + +bimapValName :: Name +bimapValName = 'bimap + +pureValName :: Name +pureValName = 'pure + +apValName :: Name +apValName = '(<*>) + +liftA2ValName :: Name +liftA2ValName = 'liftA2 + +mappendValName :: Name +mappendValName = 'mappend + +memptyValName :: Name +memptyValName = 'mempty + +bifoldableTypeName :: Name +bifoldableTypeName = ''Bifoldable + +bitraversableTypeName :: Name +bitraversableTypeName = ''Bitraversable + +bifoldrValName :: Name +bifoldrValName = 'bifoldr + +bifoldMapValName :: Name +bifoldMapValName = 'bifoldMap + +bitraverseValName :: Name +bitraverseValName = 'bitraverse + +appEndoValName :: Name +appEndoValName = 'appEndo + +dualDataName :: Name +dualDataName = 'Dual + +endoDataName :: Name +endoDataName = 'Endo + +getDualValName :: Name +getDualValName = 'getDual diff --git a/src/Data/Bifunctor/Tannen.hs b/src/Data/Bifunctor/Tannen.hs new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Tannen.hs @@ -0,0 +1,158 @@ +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE TypeFamilies #-} +{-# LANGUAGE TypeOperators #-} + +----------------------------------------------------------------------------- +-- | +-- 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.Bifunctor.Swap (Swap (..)) +import Data.Biapplicative +import Data.Bifoldable +import Data.Bifoldable1 (Bifoldable1(..)) +import Data.Bitraversable +import Data.Foldable1 (Foldable1(..)) +import Data.Functor.Classes + +import GHC.Generics + +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, Generic) +deriving instance Functor f => Generic1 (Tannen f p a) + +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 '}' + +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 (Foldable1 f, Bifoldable1 p) => Bifoldable1 (Tannen f p) where + bifoldMap1 f g = foldMap1 (bifoldMap1 f g) . runTannen + {-# INLINE bifoldMap1 #-} + +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) + +-- | @since 5.6.1 +instance (Functor f, Swap p) => Swap (Tannen f p) where + swap = Tannen . fmap swap . runTannen diff --git a/src/Data/Bifunctor/Wrapped.hs b/src/Data/Bifunctor/Wrapped.hs new file mode 100644 --- /dev/null +++ b/src/Data/Bifunctor/Wrapped.hs @@ -0,0 +1,97 @@ +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE TypeFamilies #-} + +----------------------------------------------------------------------------- +-- | +-- 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 + +import Data.Biapplicative +import Data.Bifoldable +import Data.Bifoldable1 (Bifoldable1(..)) +import Data.Bitraversable +import Data.Functor.Classes +import GHC.Generics + +-- | 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, Generic, Generic1) + +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 '}' + +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 Bifoldable1 p => Bifoldable1 (WrappedBifunctor p) where + bifoldMap1 f g = bifoldMap1 f g . unwrapBifunctor + {-# INLINE bifoldMap1 #-} + +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/src/Data/Bitraversable.hs b/src/Data/Bitraversable.hs deleted file mode 100644 --- a/src/Data/Bitraversable.hs +++ /dev/null @@ -1,102 +0,0 @@ ------------------------------------------------------------------------------ --- | --- Module : Data.Bitraversable --- Copyright : (C) 2011 Edward Kmett, --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Bitraversable - ( Bitraversable(..) - , bifor - , biforM - , bimapAccumL - , bimapAccumR - , bimapDefault - , bifoldMapDefault - ) where - -import Control.Applicative -import Data.Monoid -import Data.Bifunctor -import Data.Bifoldable - -class (Bifunctor t, Bifoldable t) => Bitraversable t where - bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> t a b -> f (t c d) - bitraverse f g = bisequenceA . bimap f g - - bisequenceA :: Applicative f => t (f a) (f b) -> f (t a b) - bisequenceA = bitraverse id id - - bimapM :: Monad m => (a -> m c) -> (b -> m d) -> t a b -> m (t c d) - bimapM f g = unwrapMonad . bitraverse (WrapMonad . f) (WrapMonad . g) - - bisequence :: Monad m => t (m a) (m b) -> m (t a b) - bisequence = bimapM id id - -instance Bitraversable (,) where - bitraverse f g (a, b) = (,) <$> f a <*> g b - -instance Bitraversable Either where - bitraverse f _ (Left a) = Left <$> f a - bitraverse _ g (Right b) = Right <$> g b - -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 :: (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 - - --- 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) - -instance Applicative (StateL s) where - pure x = StateL (\ s -> (s, x)) - StateL kf <*> StateL kv = StateL $ \ s -> - let (s', f) = kf s - (s'', v) = kv s' - in (s'', f v) - -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 - --- 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) - -instance Applicative (StateR s) where - pure x = StateR (\ s -> (s, x)) - StateR kf <*> StateR kv = StateR $ \ s -> - let (s', v) = kv s - (s'', f) = kf s' - in (s'', f v) - -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 - -newtype Id a = Id { getId :: a } - -instance Functor Id where - fmap f (Id x) = Id (f x) - -instance Applicative Id where - pure = Id - Id f <*> Id x = Id (f x) - -bimapDefault :: Bitraversable t => (a -> b) -> (c -> d) -> t a c -> t b d -bimapDefault f g = getId . bitraverse (Id . f) (Id . g) - -bifoldMapDefault :: (Bitraversable t, Monoid m) => (a -> m) -> (b -> m) -> t a b -> m -bifoldMapDefault f g = getConst . bitraverse (Const . f) (Const . g) diff --git a/src/Data/Semigroup/Bifoldable.hs b/src/Data/Semigroup/Bifoldable.hs deleted file mode 100644 --- a/src/Data/Semigroup/Bifoldable.hs +++ /dev/null @@ -1,67 +0,0 @@ ------------------------------------------------------------------------------ --- | --- Module : Data.Semigroup.Foldable --- Copyright : (C) 2011 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Semigroup.Bifoldable - ( Bifoldable1(..) - , bitraverse1_ - , bifor1_ - , bisequenceA1_ - , bifoldMapDefault1 - ) where - -import Prelude hiding (foldr) -import Data.Bifoldable -import Data.Functor.Apply -import Data.Semigroup - -class Bifoldable t => Bifoldable1 t where - bifold1 :: Semigroup m => t m m -> m - bifold1 = bifoldMap1 id id - - bifoldMap1 :: Semigroup m => (a -> m) -> (b -> m) -> t a b -> m - bifoldMap1 f g = maybe (error "bifoldMap1") id . getOption . bifoldMap (Option . Just . f) (Option . Just . g) - -instance Bifoldable1 Either where - bifoldMap1 f _ (Left a) = f a - bifoldMap1 _ g (Right b) = g b - -instance Bifoldable1 (,) where - bifoldMap1 f g (a, b) = f a <> g b - -newtype Act f a = Act { getAct :: f a } - -instance Apply f => Semigroup (Act f a) where - Act a <> Act b = Act (a .> b) - -instance Functor f => Functor (Act f) where - fmap f (Act a) = Act (f <$> a) - b <$ Act a = Act (b <$ a) - -bitraverse1_ :: (Bifoldable1 t, Apply f) => (a -> f b) -> (c -> f d) -> t a c -> f () -bitraverse1_ f g t = getAct (bifoldMap1 (Act . ignore . f) (Act . ignore . g) t) -{-# INLINE bitraverse1_ #-} - -bifor1_ :: (Bifoldable1 t, Apply f) => t a c -> (a -> f b) -> (c -> f d) -> f () -bifor1_ t f g = bitraverse1_ f g t -{-# INLINE bifor1_ #-} - -ignore :: Functor f => f a -> f () -ignore = (() <$) - -bisequenceA1_ :: (Bifoldable1 t, Apply f) => t (f a) (f b) -> f () -bisequenceA1_ t = getAct (bifoldMap1 (Act . ignore) (Act . ignore) t) -{-# INLINE bisequenceA1_ #-} - --- | Usable default for foldMap, but only if you define bifoldMap1 yourself -bifoldMapDefault1 :: (Bifoldable1 t, Monoid m) => (a -> m) -> (b -> m) -> t a b -> m -bifoldMapDefault1 f g = unwrapMonoid . bifoldMap (WrapMonoid . f) (WrapMonoid . g) -{-# INLINE bifoldMapDefault1 #-} - diff --git a/src/Data/Semigroup/Bitraversable.hs b/src/Data/Semigroup/Bitraversable.hs deleted file mode 100644 --- a/src/Data/Semigroup/Bitraversable.hs +++ /dev/null @@ -1,39 +0,0 @@ ------------------------------------------------------------------------------ --- | --- Module : Data.Semigroup.Bitraversable --- Copyright : (C) 2011 Edward Kmett --- License : BSD-style (see the file LICENSE) --- --- Maintainer : Edward Kmett --- Stability : provisional --- Portability : portable --- ----------------------------------------------------------------------------- -module Data.Semigroup.Bitraversable - ( Bitraversable1(..) - , bifoldMap1Default - ) where - -import Control.Applicative -import Data.Functor.Apply -import Data.Semigroup.Bifoldable -import Data.Bitraversable -import Data.Bifunctor -import Data.Semigroup - -class (Bifoldable1 t, Bitraversable t) => Bitraversable1 t where - bitraverse1 :: Apply f => (a -> f b) -> (c -> f d) -> t a c -> f (t b d) - bitraverse1 f g = bisequence1 . bimap f g - - bisequence1 :: Apply f => t (f a) (f b) -> f (t a b) - bisequence1 = bitraverse1 id id - -bifoldMap1Default :: (Bitraversable1 t, Semigroup m) => (a -> m) -> (b -> m) -> t a b -> m -bifoldMap1Default f g = getConst . bitraverse1 (Const . f) (Const . g) - -instance Bitraversable1 Either where - bitraverse1 f _ (Left a) = Left <$> f a - bitraverse1 _ g (Right b) = Right <$> g b - -instance Bitraversable1 (,) where - bitraverse1 f g (a, b) = (,) <$> f a <.> g b diff --git a/tests/BifunctorSpec.hs b/tests/BifunctorSpec.hs new file mode 100644 --- /dev/null +++ b/tests/BifunctorSpec.hs @@ -0,0 +1,498 @@ +{-# LANGUAGE DeriveFoldable #-} +{-# LANGUAGE DeriveFunctor #-} +{-# LANGUAGE DeriveTraversable #-} +{-# LANGUAGE EmptyCase #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE ExistentialQuantification #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE GADTs #-} +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE MagicHash #-} +{-# LANGUAGE RankNTypes #-} +{-# LANGUAGE RoleAnnotations #-} +{-# LANGUAGE StandaloneDeriving #-} +{-# LANGUAGE TemplateHaskell #-} +{-# LANGUAGE TupleSections #-} +{-# LANGUAGE TypeFamilies #-} +{-# LANGUAGE TypeOperators #-} +{-# LANGUAGE UndecidableInstances #-} + +{-# OPTIONS_GHC -Wno-name-shadowing #-} +{-# OPTIONS_GHC -Wno-unused-matches #-} +{-# OPTIONS_GHC -Wno-unused-foralls #-} + +{-| +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) + +------------------------------------------------------------------------------- + +-- 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) +type role Empty2 nominal nominal + +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 + deriving (Functor, Foldable, Traversable) + +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 + deriving Functor + +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 + deriving (Functor, Foldable, Traversable) + +data family OneTwoComposeFam (j :: * -> *) (k :: * -> * -> *) x y +newtype instance OneTwoComposeFam f g a b = OneTwoComposeFam (f (g a b)) + deriving ( Arbitrary, Eq, Show + , Functor, Foldable, Traversable + ) + +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)) + deriving (Functor, Foldable, Traversable) + +data family IntHashFunFam x y +data instance IntHashFunFam a b + = IntHashFunFam ((((a -> Int#) -> b) -> Int#) -> a) + deriving Functor + +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) + deriving (Functor, Foldable, Traversable) + +------------------------------------------------------------------------------- + +-- 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) +$(deriveBitraversable ''TyCon82) + +-- Data families + +$(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) + +------------------------------------------------------------------------------- + +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) + 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) diff --git a/tests/Spec.hs b/tests/Spec.hs new file mode 100644 --- /dev/null +++ b/tests/Spec.hs @@ -0,0 +1,1 @@ +{-# OPTIONS_GHC -F -pgmF hspec-discover #-} diff --git a/tests/T89Spec.hs b/tests/T89Spec.hs new file mode 100644 --- /dev/null +++ b/tests/T89Spec.hs @@ -0,0 +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 ()