syb 0.7 → 0.7.1
raw patch · 58 files changed
+4667/−4632 lines, 58 filessetup-changednew-uploader
Files
- ChangeLog +5/−0
- LICENSE +83/−83
- README +0/−43
- README.md +43/−0
- Setup.lhs +3/−3
- src/Data/Generics.hs +39/−39
- src/Data/Generics/Aliases.hs +439/−439
- src/Data/Generics/Basics.hs +23/−23
- src/Data/Generics/Instances.hs +190/−190
- src/Data/Generics/Schemes.hs +208/−182
- src/Data/Generics/Text.hs +131/−131
- src/Data/Generics/Twins.hs +294/−291
- src/Generics/SYB.hs +17/−17
- src/Generics/SYB/Aliases.hs +17/−17
- src/Generics/SYB/Basics.hs +17/−17
- src/Generics/SYB/Builders.hs +17/−17
- src/Generics/SYB/Instances.hs +17/−17
- src/Generics/SYB/Schemes.hs +17/−17
- src/Generics/SYB/Text.hs +17/−17
- src/Generics/SYB/Twins.hs +17/−17
- syb.cabal +66/−65
- tests/Bits.hs +225/−225
- tests/Builders.hs +19/−19
- tests/CompanyDatatypes.hs +39/−39
- tests/Datatype.hs +55/−55
- tests/Encode.hs +88/−88
- tests/Ext.hs +30/−30
- tests/Ext1.hs +128/−128
- tests/Ext2.hs +65/−65
- tests/FoldTree.hs +73/−73
- tests/FreeNames.hs +118/−118
- tests/GEq.hs +21/−21
- tests/GMapQAssoc.hs +68/−68
- tests/GRead.hs +45/−45
- tests/GRead2.hs +75/−75
- tests/GShow.hs +52/−52
- tests/GShow2.hs +47/−47
- tests/GZip.hs +46/−46
- tests/GenUpTo.hs +94/−94
- tests/GetC.hs +121/−121
- tests/HList.hs +61/−61
- tests/HOPat.hs +66/−66
- tests/Labels.hs +30/−30
- tests/LocalQuantors.hs +21/−21
- tests/Main.hs +82/−82
- tests/NestedDatatypes.hs +43/−43
- tests/Newtype.hs +20/−20
- tests/Paradise.hs +29/−29
- tests/Perm.hs +139/−139
- tests/Polymatch.hs +70/−70
- tests/Reify.hs +413/−413
- tests/Strings.hs +21/−21
- tests/Tree.hs +62/−62
- tests/Twin.hs +90/−90
- tests/Typecase1.hs +58/−58
- tests/Typecase2.hs +61/−61
- tests/Where.hs +125/−125
- tests/XML.hs +207/−207
+ ChangeLog view
@@ -0,0 +1,5 @@+2019-06-15 Sergey Vinokurov <serg.foo@gmail.com>++ * 0.7.1: Define recursive traversals in two parts, non-recursive+ wrapper and recursive local helper to facilitate inlining and+ avoid passing the same argument to all recursive calls
LICENSE view
@@ -1,83 +1,83 @@-This library (libraries/syb) is derived from code from several -sources: - - * Code from the GHC project which is largely (c) The University of - Glasgow, and distributable under a BSD-style license (see below), - - * Code from the Haskell 98 Report which is (c) Simon Peyton Jones - and freely redistributable (but see the full license for - restrictions). - - * Code from the Haskell Foreign Function Interface specification, - which is (c) Manuel M. T. Chakravarty and freely redistributable - (but see the full license for restrictions). - -The full text of these licenses is reproduced below. All of the -licenses are BSD-style or compatible. - ------------------------------------------------------------------------------ - -The Glasgow Haskell Compiler License - -Copyright 2004, The University Court of the University of Glasgow. -All rights reserved. - -Redistribution and use in source and binary forms, with or without -modification, are permitted provided that the following conditions are met: - -- Redistributions of source code must retain the above copyright notice, -this list of conditions and the following disclaimer. - -- 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. - -- Neither name of the University nor the names of its contributors may be -used to endorse or promote products derived from this software without -specific prior written permission. - -THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY COURT OF THE UNIVERSITY OF -GLASGOW AND THE CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, -INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND -FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE -UNIVERSITY COURT OF THE UNIVERSITY OF GLASGOW OR THE CONTRIBUTORS BE LIABLE -FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL -DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR -SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER -CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY -OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH -DAMAGE. - ------------------------------------------------------------------------------ - -Code derived from the document "Report on the Programming Language -Haskell 98", is distributed under the following license: - - Copyright (c) 2002 Simon Peyton Jones - - The authors intend this Report to belong to the entire Haskell - community, and so we grant permission to copy and distribute it for - any purpose, provided that it is reproduced in its entirety, - including this Notice. Modified versions of this Report may also be - copied and distributed for any purpose, provided that the modified - version is clearly presented as such, and that it does not claim to - be a definition of the Haskell 98 Language. - ------------------------------------------------------------------------------ - -Code derived from the document "The Haskell 98 Foreign Function -Interface, An Addendum to the Haskell 98 Report" is distributed under -the following license: - - Copyright (c) 2002 Manuel M. T. Chakravarty - - The authors intend this Report to belong to the entire Haskell - community, and so we grant permission to copy and distribute it for - any purpose, provided that it is reproduced in its entirety, - including this Notice. Modified versions of this Report may also be - copied and distributed for any purpose, provided that the modified - version is clearly presented as such, and that it does not claim to - be a definition of the Haskell 98 Foreign Function Interface. - ------------------------------------------------------------------------------ +This library (libraries/syb) is derived from code from several+sources: ++ * Code from the GHC project which is largely (c) The University of+ Glasgow, and distributable under a BSD-style license (see below),++ * Code from the Haskell 98 Report which is (c) Simon Peyton Jones+ and freely redistributable (but see the full license for+ restrictions).++ * Code from the Haskell Foreign Function Interface specification,+ which is (c) Manuel M. T. Chakravarty and freely redistributable+ (but see the full license for restrictions).++The full text of these licenses is reproduced below. All of the+licenses are BSD-style or compatible.++-----------------------------------------------------------------------------++The Glasgow Haskell Compiler License++Copyright 2004, The University Court of the University of Glasgow. +All rights reserved.++Redistribution and use in source and binary forms, with or without+modification, are permitted provided that the following conditions are met:++- Redistributions of source code must retain the above copyright notice,+this list of conditions and the following disclaimer.+ +- 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.+ +- Neither name of the University nor the names of its contributors may be+used to endorse or promote products derived from this software without+specific prior written permission. ++THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY COURT OF THE UNIVERSITY OF+GLASGOW AND THE CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,+INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND+FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE+UNIVERSITY COURT OF THE UNIVERSITY OF GLASGOW OR THE CONTRIBUTORS BE LIABLE+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY+OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH+DAMAGE.++-----------------------------------------------------------------------------++Code derived from the document "Report on the Programming Language+Haskell 98", is distributed under the following license:++ Copyright (c) 2002 Simon Peyton Jones++ The authors intend this Report to belong to the entire Haskell+ community, and so we grant permission to copy and distribute it for+ any purpose, provided that it is reproduced in its entirety,+ including this Notice. Modified versions of this Report may also be+ copied and distributed for any purpose, provided that the modified+ version is clearly presented as such, and that it does not claim to+ be a definition of the Haskell 98 Language.++-----------------------------------------------------------------------------++Code derived from the document "The Haskell 98 Foreign Function+Interface, An Addendum to the Haskell 98 Report" is distributed under+the following license:++ Copyright (c) 2002 Manuel M. T. Chakravarty++ The authors intend this Report to belong to the entire Haskell+ community, and so we grant permission to copy and distribute it for+ any purpose, provided that it is reproduced in its entirety,+ including this Notice. Modified versions of this Report may also be+ copied and distributed for any purpose, provided that the modified+ version is clearly presented as such, and that it does not claim to+ be a definition of the Haskell 98 Foreign Function Interface.++-----------------------------------------------------------------------------
− README
@@ -1,43 +0,0 @@-syb: Scrap Your Boilerplate! -================================================================================ - -Scrap Your Boilerplate (SYB) is a library for generic programming in Haskell. It -is supported since the GHC >= 6.0 implementation of Haskell. Using this -approach, you can write generic functions such as traversal schemes (e.g., -everywhere and everything), as well as generic read, generic show and generic -equality (i.e., gread, gshow, and geq). This approach is based on just a few -primitives for type-safe cast and processing constructor applications. - -It was originally developed by Ralf Lämmel and Simon Peyton Jones. Since then, -many people have contributed with research relating to SYB or its applications. - -More information is available on the webpage: -http://www.cs.uu.nl/wiki/GenericProgramming/SYB - - -Features --------- - -* Easy generic programming with combinators -* GHC can derive Data and Typeable instances for your datatypes -* Comes with many useful generic functions - - -Requirements ------------- - -* GHC 6.10.1 or later -* Cabal 1.6 or later - - -Bugs & Support --------------- - -Please report issues or request features at the bug tracker: - - http://code.google.com/p/scrapyourboilerplate/issues/list - -For discussion about the library with the authors, maintainers, and other -interested persons use the mailing list: - - http://www.haskell.org/mailman/listinfo/generics
+ README.md view
@@ -0,0 +1,43 @@+syb: Scrap Your Boilerplate!+================================================================================++Scrap Your Boilerplate (SYB) is a library for generic programming in Haskell. It +is supported since the GHC >= 6.0 implementation of Haskell. Using this +approach, you can write generic functions such as traversal schemes (e.g., +everywhere and everything), as well as generic read, generic show and generic +equality (i.e., gread, gshow, and geq). This approach is based on just a few +primitives for type-safe cast and processing constructor applications. ++It was originally developed by Ralf Lämmel and Simon Peyton Jones. Since then,+many people have contributed with research relating to SYB or its applications. ++More information is available on the webpage: +http://www.cs.uu.nl/wiki/GenericProgramming/SYB+++Features+--------++* Easy generic programming with combinators+* GHC can derive Data and Typeable instances for your datatypes+* Comes with many useful generic functions+++Requirements+------------++* GHC 6.10.1 or later+* Cabal 1.6 or later+++Bugs & Support+--------------++Please report issues or request features at the bug tracker:++ https://github.com/dreixel/syb/issues++For discussion about the library with the authors, maintainers, and other+interested persons use the mailing list:++ http://www.haskell.org/mailman/listinfo/generics
Setup.lhs view
@@ -1,3 +1,3 @@-#!/usr/bin/env runhaskell -> import Distribution.Simple -> main = defaultMain +#!/usr/bin/env runhaskell+> import Distribution.Simple+> main = defaultMain
src/Data/Generics.hs view
@@ -1,39 +1,39 @@-{-# LANGUAGE CPP #-} ------------------------------------------------------------------------------ --- | --- Module : Data.Generics --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (uses Data.Generics.Basics) --- --- \"Scrap your boilerplate\" --- Generic programming in Haskell --- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. To scrap your --- boilerplate it is sufficient to import the present module, which simply --- re-exports all themes of the Data.Generics library. --- ------------------------------------------------------------------------------ - -module Data.Generics ( - - -- * All Data.Generics modules - module Data.Data, -- primitives and instances of the Data class - module Data.Generics.Aliases, -- aliases for type case, generic types - module Data.Generics.Schemes, -- traversal schemes (everywhere etc.) - module Data.Generics.Text, -- generic read and show - module Data.Generics.Twins, -- twin traversal, e.g., generic eq - module Data.Generics.Builders, -- term builders - - ) where - ------------------------------------------------------------------------------- - -import Data.Data -import Data.Generics.Instances () -import Data.Generics.Aliases -import Data.Generics.Schemes -import Data.Generics.Text -import Data.Generics.Twins -import Data.Generics.Builders +{-# LANGUAGE CPP #-}+-----------------------------------------------------------------------------+-- |+-- Module : Data.Generics+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (uses Data.Generics.Basics)+--+-- \"Scrap your boilerplate\" --- Generic programming in Haskell +-- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. To scrap your+-- boilerplate it is sufficient to import the present module, which simply+-- re-exports all themes of the Data.Generics library.+--+-----------------------------------------------------------------------------++module Data.Generics (++ -- * All Data.Generics modules+ module Data.Data, -- primitives and instances of the Data class+ module Data.Generics.Aliases, -- aliases for type case, generic types+ module Data.Generics.Schemes, -- traversal schemes (everywhere etc.)+ module Data.Generics.Text, -- generic read and show+ module Data.Generics.Twins, -- twin traversal, e.g., generic eq+ module Data.Generics.Builders, -- term builders++ ) where++------------------------------------------------------------------------------++import Data.Data+import Data.Generics.Instances ()+import Data.Generics.Aliases+import Data.Generics.Schemes+import Data.Generics.Text+import Data.Generics.Twins+import Data.Generics.Builders
src/Data/Generics/Aliases.hs view
@@ -1,439 +1,439 @@-{-# LANGUAGE RankNTypes, CPP #-} ------------------------------------------------------------------------------ --- | --- Module : Data.Generics.Aliases --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- \"Scrap your boilerplate\" --- Generic programming in Haskell --- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. --- The present module provides a number of declarations for typical generic --- function types, corresponding type case, and others. --- ------------------------------------------------------------------------------ - -module Data.Generics.Aliases ( - - -- * Combinators to \"make\" generic functions via cast - mkT, mkQ, mkM, mkMp, mkR, - ext0, extT, extQ, extM, extMp, extB, extR, - - -- * Type synonyms for generic function types - GenericT, - GenericQ, - GenericM, - GenericB, - GenericR, - Generic, - Generic'(..), - GenericT'(..), - GenericQ'(..), - GenericM'(..), - - -- * Ingredients of generic functions - orElse, - - -- * Function combinators on generic functions - recoverMp, - recoverQ, - choiceMp, - choiceQ, - - -- * Type extension for unary type constructors - ext1, - ext1T, - ext1M, - ext1Q, - ext1R, - ext1B, - - -- * Type extension for binary type constructors - ext2T, - ext2M, - ext2Q, - ext2R, - ext2B - - ) where - -#ifdef __HADDOCK__ -import Prelude -#endif -import Control.Monad -import Data.Data - ------------------------------------------------------------------------------- --- --- Combinators to "make" generic functions --- We use type-safe cast in a number of ways to make generic functions. --- ------------------------------------------------------------------------------- - --- | Make a generic transformation; --- start from a type-specific case; --- preserve the term otherwise --- -mkT :: ( Typeable a - , Typeable b - ) - => (b -> b) - -> a - -> a -mkT = extT id - - --- | Make a generic query; --- start from a type-specific case; --- return a constant otherwise --- -mkQ :: ( Typeable a - , Typeable b - ) - => r - -> (b -> r) - -> a - -> r -(r `mkQ` br) a = case cast a of - Just b -> br b - Nothing -> r - - --- | Make a generic monadic transformation; --- start from a type-specific case; --- resort to return otherwise --- -mkM :: ( Monad m - , Typeable a - , Typeable b - ) - => (b -> m b) - -> a - -> m a -mkM = extM return - - -{- - -For the remaining definitions, we stick to a more concise style, i.e., -we fold maybes with "maybe" instead of case ... of ..., and we also -use a point-free style whenever possible. - --} - - --- | Make a generic monadic transformation for MonadPlus; --- use \"const mzero\" (i.e., failure) instead of return as default. --- -mkMp :: ( MonadPlus m - , Typeable a - , Typeable b - ) - => (b -> m b) - -> a - -> m a -mkMp = extM (const mzero) - - --- | Make a generic builder; --- start from a type-specific ase; --- resort to no build (i.e., mzero) otherwise --- -mkR :: ( MonadPlus m - , Typeable a - , Typeable b - ) - => m b -> m a -mkR f = mzero `extR` f - - --- | Flexible type extension -ext0 :: (Typeable a, Typeable b) => c a -> c b -> c a -ext0 def ext = maybe def id (gcast ext) - - --- | Extend a generic transformation by a type-specific case -extT :: ( Typeable a - , Typeable b - ) - => (a -> a) - -> (b -> b) - -> a - -> a -extT def ext = unT ((T def) `ext0` (T ext)) - - --- | Extend a generic query by a type-specific case -extQ :: ( Typeable a - , Typeable b - ) - => (a -> q) - -> (b -> q) - -> a - -> q -extQ f g a = maybe (f a) g (cast a) - - --- | Extend a generic monadic transformation by a type-specific case -extM :: ( Monad m - , Typeable a - , Typeable b - ) - => (a -> m a) -> (b -> m b) -> a -> m a -extM def ext = unM ((M def) `ext0` (M ext)) - - --- | Extend a generic MonadPlus transformation by a type-specific case -extMp :: ( MonadPlus m - , Typeable a - , Typeable b - ) - => (a -> m a) -> (b -> m b) -> a -> m a -extMp = extM - - --- | Extend a generic builder -extB :: ( Typeable a - , Typeable b - ) - => a -> b -> a -extB a = maybe a id . cast - - --- | Extend a generic reader -extR :: ( Monad m - , Typeable a - , Typeable b - ) - => m a -> m b -> m a -extR def ext = unR ((R def) `ext0` (R ext)) - - - ------------------------------------------------------------------------------- --- --- Type synonyms for generic function types --- ------------------------------------------------------------------------------- - - --- | Generic transformations, --- i.e., take an \"a\" and return an \"a\" --- -type GenericT = forall a. Data a => a -> a - - --- | Generic queries of type \"r\", --- i.e., take any \"a\" and return an \"r\" --- -type GenericQ r = forall a. Data a => a -> r - - --- | Generic monadic transformations, --- i.e., take an \"a\" and compute an \"a\" --- -type GenericM m = forall a. Data a => a -> m a - - --- | Generic builders --- i.e., produce an \"a\". --- -type GenericB = forall a. Data a => a - - --- | Generic readers, say monadic builders, --- i.e., produce an \"a\" with the help of a monad \"m\". --- -type GenericR m = forall a. Data a => m a - - --- | The general scheme underlying generic functions --- assumed by gfoldl; there are isomorphisms such as --- GenericT = Generic T. --- -type Generic c = forall a. Data a => a -> c a - - --- | Wrapped generic functions; --- recall: [Generic c] would be legal but [Generic' c] not. --- -data Generic' c = Generic' { unGeneric' :: Generic c } - - --- | Other first-class polymorphic wrappers -newtype GenericT' = GT { unGT :: forall a. Data a => a -> a } -newtype GenericQ' r = GQ { unGQ :: GenericQ r } -newtype GenericM' m = GM { unGM :: forall a. Data a => a -> m a } - - --- | Left-biased choice on maybes -orElse :: Maybe a -> Maybe a -> Maybe a -x `orElse` y = case x of - Just _ -> x - Nothing -> y - - -{- - -The following variations take "orElse" to the function -level. Furthermore, we generalise from "Maybe" to any -"MonadPlus". This makes sense for monadic transformations and -queries. We say that the resulting combinators modell choice. We also -provide a prime example of choice, that is, recovery from failure. In -the case of transformations, we recover via return whereas for -queries a given constant is returned. - --} - --- | Choice for monadic transformations -choiceMp :: MonadPlus m => GenericM m -> GenericM m -> GenericM m -choiceMp f g x = f x `mplus` g x - - --- | Choice for monadic queries -choiceQ :: MonadPlus m => GenericQ (m r) -> GenericQ (m r) -> GenericQ (m r) -choiceQ f g x = f x `mplus` g x - - --- | Recover from the failure of monadic transformation by identity -recoverMp :: MonadPlus m => GenericM m -> GenericM m -recoverMp f = f `choiceMp` return - - --- | Recover from the failure of monadic query by a constant -recoverQ :: MonadPlus m => r -> GenericQ (m r) -> GenericQ (m r) -recoverQ r f = f `choiceQ` const (return r) - - - ------------------------------------------------------------------------------- --- Type extension for unary type constructors ------------------------------------------------------------------------------- - -#if __GLASGOW_HASKELL__ >= 707 -#define Typeable1 Typeable -#define Typeable2 Typeable -#endif - --- | Flexible type extension -ext1 :: (Data a, Typeable1 t) - => c a - -> (forall d. Data d => c (t d)) - -> c a -ext1 def ext = maybe def id (dataCast1 ext) - - --- | Type extension of transformations for unary type constructors -ext1T :: (Data d, Typeable1 t) - => (forall e. Data e => e -> e) - -> (forall f. Data f => t f -> t f) - -> d -> d -ext1T def ext = unT ((T def) `ext1` (T ext)) - - --- | Type extension of monadic transformations for type constructors -ext1M :: (Monad m, Data d, Typeable1 t) - => (forall e. Data e => e -> m e) - -> (forall f. Data f => t f -> m (t f)) - -> d -> m d -ext1M def ext = unM ((M def) `ext1` (M ext)) - - --- | Type extension of queries for type constructors -ext1Q :: (Data d, Typeable1 t) - => (d -> q) - -> (forall e. Data e => t e -> q) - -> d -> q -ext1Q def ext = unQ ((Q def) `ext1` (Q ext)) - - --- | Type extension of readers for type constructors -ext1R :: (Monad m, Data d, Typeable1 t) - => m d - -> (forall e. Data e => m (t e)) - -> m d -ext1R def ext = unR ((R def) `ext1` (R ext)) - - --- | Type extension of builders for type constructors -ext1B :: (Data a, Typeable1 t) - => a - -> (forall b. Data b => (t b)) - -> a -ext1B def ext = unB ((B def) `ext1` (B ext)) - ------------------------------------------------------------------------------- --- Type extension for binary type constructors ------------------------------------------------------------------------------- - --- | Flexible type extension -ext2 :: (Data a, Typeable2 t) - => c a - -> (forall d1 d2. (Data d1, Data d2) => c (t d1 d2)) - -> c a -ext2 def ext = maybe def id (dataCast2 ext) - - --- | Type extension of transformations for unary type constructors -ext2T :: (Data d, Typeable2 t) - => (forall e. Data e => e -> e) - -> (forall d1 d2. (Data d1, Data d2) => t d1 d2 -> t d1 d2) - -> d -> d -ext2T def ext = unT ((T def) `ext2` (T ext)) - - --- | Type extension of monadic transformations for type constructors -ext2M :: (Monad m, Data d, Typeable2 t) - => (forall e. Data e => e -> m e) - -> (forall d1 d2. (Data d1, Data d2) => t d1 d2 -> m (t d1 d2)) - -> d -> m d -ext2M def ext = unM ((M def) `ext2` (M ext)) - - --- | Type extension of queries for type constructors -ext2Q :: (Data d, Typeable2 t) - => (d -> q) - -> (forall d1 d2. (Data d1, Data d2) => t d1 d2 -> q) - -> d -> q -ext2Q def ext = unQ ((Q def) `ext2` (Q ext)) - - --- | Type extension of readers for type constructors -ext2R :: (Monad m, Data d, Typeable2 t) - => m d - -> (forall d1 d2. (Data d1, Data d2) => m (t d1 d2)) - -> m d -ext2R def ext = unR ((R def) `ext2` (R ext)) - - --- | Type extension of builders for type constructors -ext2B :: (Data a, Typeable2 t) - => a - -> (forall d1 d2. (Data d1, Data d2) => (t d1 d2)) - -> a -ext2B def ext = unB ((B def) `ext2` (B ext)) - ------------------------------------------------------------------------------- --- --- Type constructors for type-level lambdas --- ------------------------------------------------------------------------------- - - --- | The type constructor for transformations -newtype T x = T { unT :: x -> x } - --- | The type constructor for transformations -newtype M m x = M { unM :: x -> m x } - --- | The type constructor for queries -newtype Q q x = Q { unQ :: x -> q } - --- | The type constructor for readers -newtype R m x = R { unR :: m x } - --- | The type constructor for builders -newtype B x = B {unB :: x} +{-# LANGUAGE RankNTypes, CPP #-}+-----------------------------------------------------------------------------+-- |+-- Module : Data.Generics.Aliases+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- \"Scrap your boilerplate\" --- Generic programming in Haskell +-- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>.+-- The present module provides a number of declarations for typical generic+-- function types, corresponding type case, and others.+--+-----------------------------------------------------------------------------++module Data.Generics.Aliases (++ -- * Combinators to \"make\" generic functions via cast+ mkT, mkQ, mkM, mkMp, mkR,+ ext0, extT, extQ, extM, extMp, extB, extR,++ -- * Type synonyms for generic function types+ GenericT,+ GenericQ,+ GenericM,+ GenericB,+ GenericR,+ Generic,+ Generic'(..),+ GenericT'(..),+ GenericQ'(..),+ GenericM'(..),++ -- * Ingredients of generic functions+ orElse,++ -- * Function combinators on generic functions+ recoverMp,+ recoverQ,+ choiceMp,+ choiceQ,++ -- * Type extension for unary type constructors+ ext1,+ ext1T,+ ext1M,+ ext1Q,+ ext1R,+ ext1B,++ -- * Type extension for binary type constructors+ ext2T,+ ext2M,+ ext2Q,+ ext2R,+ ext2B++ ) where++#ifdef __HADDOCK__+import Prelude+#endif+import Control.Monad+import Data.Data++------------------------------------------------------------------------------+--+-- Combinators to "make" generic functions+-- We use type-safe cast in a number of ways to make generic functions.+--+------------------------------------------------------------------------------++-- | Make a generic transformation;+-- start from a type-specific case;+-- preserve the term otherwise+--+mkT :: ( Typeable a+ , Typeable b+ )+ => (b -> b)+ -> a+ -> a+mkT = extT id+++-- | Make a generic query;+-- start from a type-specific case;+-- return a constant otherwise+--+mkQ :: ( Typeable a+ , Typeable b+ )+ => r+ -> (b -> r)+ -> a+ -> r+(r `mkQ` br) a = case cast a of+ Just b -> br b+ Nothing -> r+++-- | Make a generic monadic transformation;+-- start from a type-specific case;+-- resort to return otherwise+--+mkM :: ( Monad m+ , Typeable a+ , Typeable b+ )+ => (b -> m b)+ -> a+ -> m a+mkM = extM return+++{-++For the remaining definitions, we stick to a more concise style, i.e.,+we fold maybes with "maybe" instead of case ... of ..., and we also+use a point-free style whenever possible.++-}+++-- | Make a generic monadic transformation for MonadPlus;+-- use \"const mzero\" (i.e., failure) instead of return as default.+--+mkMp :: ( MonadPlus m+ , Typeable a+ , Typeable b+ )+ => (b -> m b)+ -> a+ -> m a+mkMp = extM (const mzero)+++-- | Make a generic builder;+-- start from a type-specific ase;+-- resort to no build (i.e., mzero) otherwise+--+mkR :: ( MonadPlus m+ , Typeable a+ , Typeable b+ )+ => m b -> m a+mkR f = mzero `extR` f+++-- | Flexible type extension+ext0 :: (Typeable a, Typeable b) => c a -> c b -> c a+ext0 def ext = maybe def id (gcast ext)+++-- | Extend a generic transformation by a type-specific case+extT :: ( Typeable a+ , Typeable b+ )+ => (a -> a)+ -> (b -> b)+ -> a+ -> a+extT def ext = unT ((T def) `ext0` (T ext))+++-- | Extend a generic query by a type-specific case+extQ :: ( Typeable a+ , Typeable b+ )+ => (a -> q)+ -> (b -> q)+ -> a+ -> q+extQ f g a = maybe (f a) g (cast a)+++-- | Extend a generic monadic transformation by a type-specific case+extM :: ( Monad m+ , Typeable a+ , Typeable b+ )+ => (a -> m a) -> (b -> m b) -> a -> m a+extM def ext = unM ((M def) `ext0` (M ext))+++-- | Extend a generic MonadPlus transformation by a type-specific case+extMp :: ( MonadPlus m+ , Typeable a+ , Typeable b+ )+ => (a -> m a) -> (b -> m b) -> a -> m a+extMp = extM+++-- | Extend a generic builder+extB :: ( Typeable a+ , Typeable b+ )+ => a -> b -> a+extB a = maybe a id . cast+++-- | Extend a generic reader+extR :: ( Monad m+ , Typeable a+ , Typeable b+ )+ => m a -> m b -> m a+extR def ext = unR ((R def) `ext0` (R ext))++++------------------------------------------------------------------------------+--+-- Type synonyms for generic function types+--+------------------------------------------------------------------------------+++-- | Generic transformations,+-- i.e., take an \"a\" and return an \"a\"+--+type GenericT = forall a. Data a => a -> a+++-- | Generic queries of type \"r\",+-- i.e., take any \"a\" and return an \"r\"+--+type GenericQ r = forall a. Data a => a -> r+++-- | Generic monadic transformations,+-- i.e., take an \"a\" and compute an \"a\"+--+type GenericM m = forall a. Data a => a -> m a+++-- | Generic builders+-- i.e., produce an \"a\".+--+type GenericB = forall a. Data a => a+++-- | Generic readers, say monadic builders,+-- i.e., produce an \"a\" with the help of a monad \"m\".+--+type GenericR m = forall a. Data a => m a+++-- | The general scheme underlying generic functions+-- assumed by gfoldl; there are isomorphisms such as+-- GenericT = Generic T.+--+type Generic c = forall a. Data a => a -> c a+++-- | Wrapped generic functions;+-- recall: [Generic c] would be legal but [Generic' c] not.+--+data Generic' c = Generic' { unGeneric' :: Generic c }+++-- | Other first-class polymorphic wrappers+newtype GenericT' = GT { unGT :: forall a. Data a => a -> a }+newtype GenericQ' r = GQ { unGQ :: GenericQ r }+newtype GenericM' m = GM { unGM :: forall a. Data a => a -> m a }+++-- | Left-biased choice on maybes+orElse :: Maybe a -> Maybe a -> Maybe a+x `orElse` y = case x of+ Just _ -> x+ Nothing -> y+++{-++The following variations take "orElse" to the function+level. Furthermore, we generalise from "Maybe" to any+"MonadPlus". This makes sense for monadic transformations and+queries. We say that the resulting combinators modell choice. We also+provide a prime example of choice, that is, recovery from failure. In+the case of transformations, we recover via return whereas for+queries a given constant is returned.++-}++-- | Choice for monadic transformations+choiceMp :: MonadPlus m => GenericM m -> GenericM m -> GenericM m+choiceMp f g x = f x `mplus` g x+++-- | Choice for monadic queries+choiceQ :: MonadPlus m => GenericQ (m r) -> GenericQ (m r) -> GenericQ (m r)+choiceQ f g x = f x `mplus` g x+++-- | Recover from the failure of monadic transformation by identity+recoverMp :: MonadPlus m => GenericM m -> GenericM m+recoverMp f = f `choiceMp` return+++-- | Recover from the failure of monadic query by a constant+recoverQ :: MonadPlus m => r -> GenericQ (m r) -> GenericQ (m r)+recoverQ r f = f `choiceQ` const (return r)++++------------------------------------------------------------------------------+-- Type extension for unary type constructors+------------------------------------------------------------------------------++#if __GLASGOW_HASKELL__ >= 707+#define Typeable1 Typeable+#define Typeable2 Typeable+#endif++-- | Flexible type extension+ext1 :: (Data a, Typeable1 t)+ => c a+ -> (forall d. Data d => c (t d))+ -> c a+ext1 def ext = maybe def id (dataCast1 ext)+++-- | Type extension of transformations for unary type constructors+ext1T :: (Data d, Typeable1 t)+ => (forall e. Data e => e -> e)+ -> (forall f. Data f => t f -> t f)+ -> d -> d+ext1T def ext = unT ((T def) `ext1` (T ext))+++-- | Type extension of monadic transformations for type constructors+ext1M :: (Monad m, Data d, Typeable1 t)+ => (forall e. Data e => e -> m e)+ -> (forall f. Data f => t f -> m (t f))+ -> d -> m d+ext1M def ext = unM ((M def) `ext1` (M ext))+++-- | Type extension of queries for type constructors+ext1Q :: (Data d, Typeable1 t)+ => (d -> q)+ -> (forall e. Data e => t e -> q)+ -> d -> q+ext1Q def ext = unQ ((Q def) `ext1` (Q ext))+++-- | Type extension of readers for type constructors+ext1R :: (Monad m, Data d, Typeable1 t)+ => m d+ -> (forall e. Data e => m (t e))+ -> m d+ext1R def ext = unR ((R def) `ext1` (R ext))+++-- | Type extension of builders for type constructors+ext1B :: (Data a, Typeable1 t)+ => a+ -> (forall b. Data b => (t b))+ -> a+ext1B def ext = unB ((B def) `ext1` (B ext))++------------------------------------------------------------------------------+-- Type extension for binary type constructors+------------------------------------------------------------------------------++-- | Flexible type extension+ext2 :: (Data a, Typeable2 t)+ => c a+ -> (forall d1 d2. (Data d1, Data d2) => c (t d1 d2))+ -> c a+ext2 def ext = maybe def id (dataCast2 ext)+++-- | Type extension of transformations for unary type constructors+ext2T :: (Data d, Typeable2 t)+ => (forall e. Data e => e -> e)+ -> (forall d1 d2. (Data d1, Data d2) => t d1 d2 -> t d1 d2)+ -> d -> d+ext2T def ext = unT ((T def) `ext2` (T ext))+++-- | Type extension of monadic transformations for type constructors+ext2M :: (Monad m, Data d, Typeable2 t)+ => (forall e. Data e => e -> m e)+ -> (forall d1 d2. (Data d1, Data d2) => t d1 d2 -> m (t d1 d2))+ -> d -> m d+ext2M def ext = unM ((M def) `ext2` (M ext))+++-- | Type extension of queries for type constructors+ext2Q :: (Data d, Typeable2 t)+ => (d -> q)+ -> (forall d1 d2. (Data d1, Data d2) => t d1 d2 -> q)+ -> d -> q+ext2Q def ext = unQ ((Q def) `ext2` (Q ext))+++-- | Type extension of readers for type constructors+ext2R :: (Monad m, Data d, Typeable2 t)+ => m d+ -> (forall d1 d2. (Data d1, Data d2) => m (t d1 d2))+ -> m d+ext2R def ext = unR ((R def) `ext2` (R ext))+++-- | Type extension of builders for type constructors+ext2B :: (Data a, Typeable2 t)+ => a+ -> (forall d1 d2. (Data d1, Data d2) => (t d1 d2))+ -> a+ext2B def ext = unB ((B def) `ext2` (B ext))++------------------------------------------------------------------------------+--+-- Type constructors for type-level lambdas+--+------------------------------------------------------------------------------+++-- | The type constructor for transformations+newtype T x = T { unT :: x -> x }++-- | The type constructor for transformations+newtype M m x = M { unM :: x -> m x }++-- | The type constructor for queries+newtype Q q x = Q { unQ :: x -> q }++-- | The type constructor for readers+newtype R m x = R { unR :: m x }++-- | The type constructor for builders+newtype B x = B {unB :: x}
src/Data/Generics/Basics.hs view
@@ -1,23 +1,23 @@------------------------------------------------------------------------------ --- | --- Module : Data.Generics.Basics --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- \"Scrap your boilerplate\" --- Generic programming in Haskell. --- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. This module provides --- the 'Data' class with its primitives for generic programming, --- which is now defined in @Data.Data@. Therefore this module simply --- re-exports @Data.Data@. --- ------------------------------------------------------------------------------ - -module Data.Generics.Basics ( - module Data.Data - ) where - -import Data.Data +-----------------------------------------------------------------------------+-- |+-- Module : Data.Generics.Basics+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- \"Scrap your boilerplate\" --- Generic programming in Haskell.+-- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. This module provides+-- the 'Data' class with its primitives for generic programming,+-- which is now defined in @Data.Data@. Therefore this module simply+-- re-exports @Data.Data@.+--+-----------------------------------------------------------------------------++module Data.Generics.Basics (+ module Data.Data+ ) where++import Data.Data
src/Data/Generics/Instances.hs view
@@ -1,190 +1,190 @@-{-# LANGUAGE DeriveDataTypeable, StandaloneDeriving, CPP #-} ------------------------------------------------------------------------------ --- | --- Module : Data.Generics.Instances --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (uses Data.Data) --- --- \"Scrap your boilerplate\" --- Generic programming in Haskell --- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. The present module --- contains thirteen 'Data' instances which are considered dubious (either --- because the types are abstract or just not meant to be traversed). --- Instances in this module might change or disappear in future releases --- of this package. --- --- (This module does not export anything. It really just defines instances.) --- ------------------------------------------------------------------------------ - -{-# OPTIONS_GHC -fno-warn-orphans #-} -module Data.Generics.Instances () where - ------------------------------------------------------------------------------- - -import Data.Data - -#ifdef __GLASGOW_HASKELL__ -#if __GLASGOW_HASKELL__ >= 611 -import GHC.IO.Handle -- So we can give Data instance for Handle -#else -import GHC.IOBase -- So we can give Data instance for IO, Handle -#endif -import GHC.Stable -- So we can give Data instance for StablePtr -import GHC.ST -- So we can give Data instance for ST -import GHC.Conc -- So we can give Data instance for TVar -import Data.IORef -- So we can give Data instance for IORef -import Control.Concurrent -- So we can give Data instance for MVar -#else -# ifdef __HUGS__ -import Hugs.Prelude( Ratio(..) ) -# endif -import System.IO -import Foreign.Ptr -import Foreign.ForeignPtr -import Foreign.StablePtr -import Control.Monad.ST -#endif - --- Version compatibility issues caused by #2760 -myMkNoRepType :: String -> DataType -#if __GLASGOW_HASKELL__ >= 611 -myMkNoRepType = mkNoRepType -#else -myMkNoRepType = mkNorepType -#endif - - ------------------------------------------------------------------------------- --- --- Instances of the Data class for Prelude-like types. --- We define top-level definitions for representations. --- ------------------------------------------------------------------------------- - - ------------------------------------------------------------------------------- --- Instances of abstract datatypes (6) ------------------------------------------------------------------------------- - -#if __GLASGOW_HASKELL__ < 801 -instance Data TypeRep where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "Data.Typeable.TypeRep" -#endif - - ------------------------------------------------------------------------------- - -instance Data TyCon where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "Data.Typeable.TyCon" - - ------------------------------------------------------------------------------- -#if __GLASGOW_HASKELL__ < 709 -deriving instance Typeable DataType -#endif - -instance Data DataType where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "Data.Generics.Basics.DataType" - - ------------------------------------------------------------------------------- - -instance Data Handle where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "GHC.IOBase.Handle" - - ------------------------------------------------------------------------------- - -instance Typeable a => Data (StablePtr a) where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "GHC.Stable.StablePtr" - - ------------------------------------------------------------------------------- - -#ifdef __GLASGOW_HASKELL__ -instance Data ThreadId where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "GHC.Conc.ThreadId" -#endif - - ------------------------------------------------------------------------------- --- Dubious instances (7) ------------------------------------------------------------------------------- - -#ifdef __GLASGOW_HASKELL__ -instance Typeable a => Data (TVar a) where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "GHC.Conc.TVar" -#endif - - ------------------------------------------------------------------------------- - -instance Typeable a => Data (MVar a) where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "GHC.Conc.MVar" - - ------------------------------------------------------------------------------- - -#ifdef __GLASGOW_HASKELL__ -instance Typeable a => Data (STM a) where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "GHC.Conc.STM" -#endif - - ------------------------------------------------------------------------------- - -instance (Typeable s, Typeable a) => Data (ST s a) where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "GHC.ST.ST" - - ------------------------------------------------------------------------------- - -instance Typeable a => Data (IORef a) where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "GHC.IOBase.IORef" - - ------------------------------------------------------------------------------- - -instance Typeable a => Data (IO a) where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "GHC.IOBase.IO" - ------------------------------------------------------------------------------- - --- --- A last resort for functions --- - -instance (Data a, Data b) => Data (a -> b) where - toConstr _ = error "toConstr" - gunfold _ _ = error "gunfold" - dataTypeOf _ = myMkNoRepType "Prelude.(->)" - dataCast2 f = gcast2 f - +{-# LANGUAGE DeriveDataTypeable, StandaloneDeriving, CPP #-}+-----------------------------------------------------------------------------+-- |+-- Module : Data.Generics.Instances+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+--+-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (uses Data.Data)+--+-- \"Scrap your boilerplate\" --- Generic programming in Haskell+-- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. The present module+-- contains thirteen 'Data' instances which are considered dubious (either+-- because the types are abstract or just not meant to be traversed).+-- Instances in this module might change or disappear in future releases+-- of this package.+--+-- (This module does not export anything. It really just defines instances.)+--+-----------------------------------------------------------------------------++{-# OPTIONS_GHC -fno-warn-orphans #-}+module Data.Generics.Instances () where++------------------------------------------------------------------------------++import Data.Data++#ifdef __GLASGOW_HASKELL__+#if __GLASGOW_HASKELL__ >= 611+import GHC.IO.Handle -- So we can give Data instance for Handle+#else+import GHC.IOBase -- So we can give Data instance for IO, Handle+#endif+import GHC.Stable -- So we can give Data instance for StablePtr+import GHC.ST -- So we can give Data instance for ST+import GHC.Conc -- So we can give Data instance for TVar+import Data.IORef -- So we can give Data instance for IORef+import Control.Concurrent -- So we can give Data instance for MVar+#else+# ifdef __HUGS__+import Hugs.Prelude( Ratio(..) )+# endif+import System.IO+import Foreign.Ptr+import Foreign.ForeignPtr+import Foreign.StablePtr+import Control.Monad.ST+#endif++-- Version compatibility issues caused by #2760+myMkNoRepType :: String -> DataType+#if __GLASGOW_HASKELL__ >= 611+myMkNoRepType = mkNoRepType+#else+myMkNoRepType = mkNorepType+#endif+++------------------------------------------------------------------------------+--+-- Instances of the Data class for Prelude-like types.+-- We define top-level definitions for representations.+--+------------------------------------------------------------------------------+++------------------------------------------------------------------------------+-- Instances of abstract datatypes (6)+------------------------------------------------------------------------------++#if __GLASGOW_HASKELL__ < 801+instance Data TypeRep where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "Data.Typeable.TypeRep"+#endif+++------------------------------------------------------------------------------++instance Data TyCon where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "Data.Typeable.TyCon"+++------------------------------------------------------------------------------+#if __GLASGOW_HASKELL__ < 709+deriving instance Typeable DataType+#endif++instance Data DataType where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "Data.Generics.Basics.DataType"+++------------------------------------------------------------------------------++instance Data Handle where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "GHC.IOBase.Handle"+++------------------------------------------------------------------------------++instance Typeable a => Data (StablePtr a) where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "GHC.Stable.StablePtr"+++------------------------------------------------------------------------------++#ifdef __GLASGOW_HASKELL__+instance Data ThreadId where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "GHC.Conc.ThreadId"+#endif+++------------------------------------------------------------------------------+-- Dubious instances (7)+------------------------------------------------------------------------------++#ifdef __GLASGOW_HASKELL__+instance Typeable a => Data (TVar a) where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "GHC.Conc.TVar"+#endif+++------------------------------------------------------------------------------++instance Typeable a => Data (MVar a) where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "GHC.Conc.MVar"+++------------------------------------------------------------------------------++#ifdef __GLASGOW_HASKELL__+instance Typeable a => Data (STM a) where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "GHC.Conc.STM"+#endif+++------------------------------------------------------------------------------++instance (Typeable s, Typeable a) => Data (ST s a) where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "GHC.ST.ST"+++------------------------------------------------------------------------------++instance Typeable a => Data (IORef a) where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "GHC.IOBase.IORef"+++------------------------------------------------------------------------------++instance Typeable a => Data (IO a) where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "GHC.IOBase.IO"++------------------------------------------------------------------------------++--+-- A last resort for functions+--++instance (Data a, Data b) => Data (a -> b) where+ toConstr _ = error "toConstr"+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = myMkNoRepType "Prelude.(->)"+ dataCast2 f = gcast2 f+
src/Data/Generics/Schemes.hs view
@@ -1,182 +1,208 @@-{-# LANGUAGE RankNTypes, ScopedTypeVariables, CPP #-} ------------------------------------------------------------------------------ --- | --- Module : Data.Generics.Schemes --- Copyright : (c) The University of Glasgow, CWI 2001--2003 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- \"Scrap your boilerplate\" --- Generic programming in Haskell --- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. The present module --- provides frequently used generic traversal schemes. --- ------------------------------------------------------------------------------ - -module Data.Generics.Schemes ( - - everywhere, - everywhere', - everywhereBut, - everywhereM, - somewhere, - everything, - everythingBut, - everythingWithContext, - listify, - something, - synthesize, - gsize, - glength, - gdepth, - gcount, - gnodecount, - gtypecount, - gfindtype - - ) where - ------------------------------------------------------------------------------- - -#ifdef __HADDOCK__ -import Prelude -#endif -import Data.Data -import Data.Generics.Aliases -import Control.Monad - - --- | Apply a transformation everywhere in bottom-up manner -everywhere :: (forall a. Data a => a -> a) - -> (forall a. Data a => a -> a) - --- Use gmapT to recurse into immediate subterms; --- recall: gmapT preserves the outermost constructor; --- post-process recursively transformed result via f --- -everywhere f = f . gmapT (everywhere f) - - --- | Apply a transformation everywhere in top-down manner -everywhere' :: (forall a. Data a => a -> a) - -> (forall a. Data a => a -> a) - --- Arguments of (.) are flipped compared to everywhere -everywhere' f = gmapT (everywhere' f) . f - - --- | Variation on everywhere with an extra stop condition -everywhereBut :: GenericQ Bool -> GenericT -> GenericT - --- Guarded to let traversal cease if predicate q holds for x -everywhereBut q f x - | q x = x - | otherwise = f (gmapT (everywhereBut q f) x) - - --- | Monadic variation on everywhere -everywhereM :: Monad m => GenericM m -> GenericM m - --- Bottom-up order is also reflected in order of do-actions -everywhereM f x = do x' <- gmapM (everywhereM f) x - f x' - - --- | Apply a monadic transformation at least somewhere -somewhere :: MonadPlus m => GenericM m -> GenericM m - --- We try "f" in top-down manner, but descent into "x" when we fail --- at the root of the term. The transformation fails if "f" fails --- everywhere, say succeeds nowhere. --- -somewhere f x = f x `mplus` gmapMp (somewhere f) x - - --- | Summarise all nodes in top-down, left-to-right order -everything :: (r -> r -> r) -> GenericQ r -> GenericQ r - --- Apply f to x to summarise top-level node; --- use gmapQ to recurse into immediate subterms; --- use ordinary foldl to reduce list of intermediate results --- -everything k f x = foldl k (f x) (gmapQ (everything k f) x) - --- | Variation of "everything" with an added stop condition -everythingBut :: (r -> r -> r) -> GenericQ (r, Bool) -> GenericQ r -everythingBut k f x = let (v, stop) = f x - in if stop - then v - else foldl k v (gmapQ (everythingBut k f) x) - --- | Summarise all nodes in top-down, left-to-right order, carrying some state --- down the tree during the computation, but not left-to-right to siblings. -everythingWithContext :: s -> (r -> r -> r) -> GenericQ (s -> (r, s)) -> GenericQ r -everythingWithContext s0 f q x = - foldl f r (gmapQ (everythingWithContext s' f q) x) - where (r, s') = q x s0 - --- | Get a list of all entities that meet a predicate -listify :: Typeable r => (r -> Bool) -> GenericQ [r] -listify p = everything (++) ([] `mkQ` (\x -> if p x then [x] else [])) - - --- | Look up a subterm by means of a maybe-typed filter -something :: GenericQ (Maybe u) -> GenericQ (Maybe u) - --- "something" can be defined in terms of "everything" --- when a suitable "choice" operator is used for reduction --- -something = everything orElse - - --- | Bottom-up synthesis of a data structure; --- 1st argument z is the initial element for the synthesis; --- 2nd argument o is for reduction of results from subterms; --- 3rd argument f updates the synthesised data according to the given term --- -synthesize :: s -> (t -> s -> s) -> GenericQ (s -> t) -> GenericQ t -synthesize z o f x = f x (foldr o z (gmapQ (synthesize z o f) x)) - - --- | Compute size of an arbitrary data structure -gsize :: Data a => a -> Int -gsize t = 1 + sum (gmapQ gsize t) - - --- | Count the number of immediate subterms of the given term -glength :: GenericQ Int -glength = length . gmapQ (const ()) - - --- | Determine depth of the given term -gdepth :: GenericQ Int -gdepth = (+) 1 . foldr max 0 . gmapQ gdepth - - --- | Determine the number of all suitable nodes in a given term -gcount :: GenericQ Bool -> GenericQ Int -gcount p = everything (+) (\x -> if p x then 1 else 0) - - --- | Determine the number of all nodes in a given term -gnodecount :: GenericQ Int -gnodecount = gcount (const True) - - --- | Determine the number of nodes of a given type in a given term -gtypecount :: Typeable a => a -> GenericQ Int -gtypecount (_::a) = gcount (False `mkQ` (\(_::a) -> True)) - - --- | Find (unambiguously) an immediate subterm of a given type -gfindtype :: (Data x, Typeable y) => x -> Maybe y -gfindtype = singleton - . foldl unJust [] - . gmapQ (Nothing `mkQ` Just) - where - unJust l (Just x) = x:l - unJust l Nothing = l - singleton [s] = Just s - singleton _ = Nothing +{-# LANGUAGE RankNTypes, ScopedTypeVariables, CPP #-}+-----------------------------------------------------------------------------+-- |+-- Module : Data.Generics.Schemes+-- Copyright : (c) The University of Glasgow, CWI 2001--2003+-- License : BSD-style (see the LICENSE file)+--+-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- \"Scrap your boilerplate\" --- Generic programming in Haskell+-- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. The present module+-- provides frequently used generic traversal schemes.+--+-----------------------------------------------------------------------------++module Data.Generics.Schemes (++ everywhere,+ everywhere',+ everywhereBut,+ everywhereM,+ somewhere,+ everything,+ everythingBut,+ everythingWithContext,+ listify,+ something,+ synthesize,+ gsize,+ glength,+ gdepth,+ gcount,+ gnodecount,+ gtypecount,+ gfindtype++ ) where++------------------------------------------------------------------------------++#ifdef __HADDOCK__+import Prelude+#endif+import Data.Data+import Data.Generics.Aliases+import Control.Monad++-- | Apply a transformation everywhere in bottom-up manner++everywhere :: (forall a. Data a => a -> a)+ -> (forall a. Data a => a -> a)++-- Use gmapT to recurse into immediate subterms;+-- recall: gmapT preserves the outermost constructor;+-- post-process recursively transformed result via f+--+everywhere f = go+ where+ go :: forall a. Data a => a -> a+ go = f . gmapT go++-- | Apply a transformation everywhere in top-down manner+everywhere' :: (forall a. Data a => a -> a)+ -> (forall a. Data a => a -> a)++-- Arguments of (.) are flipped compared to everywhere+everywhere' f = go+ where+ go :: forall a. Data a => a -> a+ go = gmapT go . f+++-- | Variation on everywhere with an extra stop condition+everywhereBut :: GenericQ Bool -> GenericT -> GenericT++-- Guarded to let traversal cease if predicate q holds for x+everywhereBut q f = go+ where+ go :: GenericT+ go x+ | q x = x+ | otherwise = f (gmapT go x)+++-- | Monadic variation on everywhere+everywhereM :: forall m. Monad m => GenericM m -> GenericM m++-- Bottom-up order is also reflected in order of do-actions+everywhereM f = go+ where+ go :: GenericM m+ go x = do+ x' <- gmapM go x+ f x'+++-- | Apply a monadic transformation at least somewhere+somewhere :: forall m. MonadPlus m => GenericM m -> GenericM m++-- We try "f" in top-down manner, but descent into "x" when we fail+-- at the root of the term. The transformation fails if "f" fails+-- everywhere, say succeeds nowhere.+--+somewhere f = go+ where+ go :: GenericM m+ go x = f x `mplus` gmapMp go x+++-- | Summarise all nodes in top-down, left-to-right order+everything :: forall r. (r -> r -> r) -> GenericQ r -> GenericQ r++-- Apply f to x to summarise top-level node;+-- use gmapQ to recurse into immediate subterms;+-- use ordinary foldl to reduce list of intermediate results+--+everything k f = go+ where+ go :: GenericQ r+ go x = foldl k (f x) (gmapQ go x)++-- | Variation of "everything" with an added stop condition+everythingBut :: forall r. (r -> r -> r) -> GenericQ (r, Bool) -> GenericQ r+everythingBut k f = go+ where+ go :: GenericQ r+ go x = let (v, stop) = f x+ in if stop+ then v+ else foldl k v (gmapQ go x)++-- | Summarise all nodes in top-down, left-to-right order, carrying some state+-- down the tree during the computation, but not left-to-right to siblings.+everythingWithContext :: forall s r. s -> (r -> r -> r) -> GenericQ (s -> (r, s)) -> GenericQ r+everythingWithContext s0 f q = go s0+ where+ go :: s -> GenericQ r+ go s x = foldl f r (gmapQ (go s') x)+ where (r, s') = q x s++-- | Get a list of all entities that meet a predicate+listify :: Typeable r => (r -> Bool) -> GenericQ [r]+listify p = everything (++) ([] `mkQ` (\x -> if p x then [x] else []))+++-- | Look up a subterm by means of a maybe-typed filter+something :: GenericQ (Maybe u) -> GenericQ (Maybe u)++-- "something" can be defined in terms of "everything"+-- when a suitable "choice" operator is used for reduction+--+something = everything orElse+++-- | Bottom-up synthesis of a data structure;+-- 1st argument z is the initial element for the synthesis;+-- 2nd argument o is for reduction of results from subterms;+-- 3rd argument f updates the synthesised data according to the given term+--+synthesize :: forall s t. s -> (t -> s -> s) -> GenericQ (s -> t) -> GenericQ t+synthesize z o f = go+ where+ go :: GenericQ t+ go x = f x (foldr o z (gmapQ go x))+++-- | Compute size of an arbitrary data structure+gsize :: Data a => a -> Int+gsize t = 1 + sum (gmapQ gsize t)+++-- | Count the number of immediate subterms of the given term+glength :: GenericQ Int+glength = length . gmapQ (const ())+++-- | Determine depth of the given term+gdepth :: GenericQ Int+gdepth = (+) 1 . foldr max 0 . gmapQ gdepth+++-- | Determine the number of all suitable nodes in a given term+gcount :: GenericQ Bool -> GenericQ Int+gcount p = everything (+) (\x -> if p x then 1 else 0)+++-- | Determine the number of all nodes in a given term+gnodecount :: GenericQ Int+gnodecount = gcount (const True)+++-- | Determine the number of nodes of a given type in a given term+gtypecount :: Typeable a => a -> GenericQ Int+gtypecount (_::a) = gcount (False `mkQ` (\(_::a) -> True))+++-- | Find (unambiguously) an immediate subterm of a given type+gfindtype :: (Data x, Typeable y) => x -> Maybe y+gfindtype = singleton+ . foldl unJust []+ . gmapQ (Nothing `mkQ` Just)+ where+ unJust l (Just x) = x:l+ unJust l Nothing = l+ singleton [s] = Just s+ singleton _ = Nothing
src/Data/Generics/Text.hs view
@@ -1,131 +1,131 @@-{-# LANGUAGE CPP #-} ------------------------------------------------------------------------------ --- | --- Module : Data.Generics.Text --- Copyright : (c) The University of Glasgow, CWI 2001--2003 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (uses Data.Generics.Basics) --- --- \"Scrap your boilerplate\" --- Generic programming in Haskell --- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. The present module --- provides generic operations for text serialisation of terms. --- ------------------------------------------------------------------------------ - -module Data.Generics.Text ( - - -- * Generic show - gshow, gshows, - - -- * Generic read - gread - - ) where - ------------------------------------------------------------------------------- - -#ifdef __HADDOCK__ -import Prelude -#endif -import Control.Monad -import Data.Data -import Data.Generics.Aliases -import Text.ParserCombinators.ReadP -import Text.Read.Lex - ------------------------------------------------------------------------------- - - --- | Generic show: an alternative to \"deriving Show\" -gshow :: Data a => a -> String -gshow x = gshows x "" - --- | Generic shows -gshows :: Data a => a -> ShowS - --- This is a prefix-show using surrounding "(" and ")", --- where we recurse into subterms with gmapQ. -gshows = ( \t -> - showChar '(' - . (showString . showConstr . toConstr $ t) - . (foldr (.) id . gmapQ ((showChar ' ' .) . gshows) $ t) - . showChar ')' - ) `extQ` (shows :: String -> ShowS) - - --- | Generic read: an alternative to \"deriving Read\" -gread :: Data a => ReadS a - -{- - -This is a read operation which insists on prefix notation. (The -Haskell 98 read deals with infix operators subject to associativity -and precedence as well.) We use fromConstrM to "parse" the input. To be -precise, fromConstrM is used for all types except String. The -type-specific case for String uses basic String read. - --} - -gread = readP_to_S gread' - - where - - -- Helper for recursive read - gread' :: Data a' => ReadP a' - gread' = allButString `extR` stringCase - - where - - -- A specific case for strings - stringCase :: ReadP String - stringCase = readS_to_P reads - - -- Determine result type - myDataType = dataTypeOf (getArg allButString) - where - getArg :: ReadP a'' -> a'' - getArg = undefined - - -- The generic default for gread - allButString = - do - -- Drop " ( " - skipSpaces -- Discard leading space - _ <- char '(' -- Parse '(' - skipSpaces -- Discard following space - - -- Do the real work - str <- parseConstr -- Get a lexeme for the constructor - con <- str2con str -- Convert it to a Constr (may fail) - x <- fromConstrM gread' con -- Read the children - - -- Drop " ) " - skipSpaces -- Discard leading space - _ <- char ')' -- Parse ')' - skipSpaces -- Discard following space - - return x - - -- Turn string into constructor driven by the requested result type, - -- failing in the monad if it isn't a constructor of this data type - str2con :: String -> ReadP Constr - str2con = maybe mzero return - . readConstr myDataType - - -- Get a Constr's string at the front of an input string - parseConstr :: ReadP String - parseConstr = - string "[]" -- Compound lexeme "[]" - <++ string "()" -- singleton "()" - <++ infixOp -- Infix operator in parantheses - <++ hsLex -- Ordinary constructors and literals - - -- Handle infix operators such as (:) - infixOp :: ReadP String - infixOp = do c1 <- char '(' - str <- munch1 (not . (==) ')') - c2 <- char ')' - return $ [c1] ++ str ++ [c2] +{-# LANGUAGE CPP #-}+-----------------------------------------------------------------------------+-- |+-- Module : Data.Generics.Text+-- Copyright : (c) The University of Glasgow, CWI 2001--2003+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (uses Data.Generics.Basics)+--+-- \"Scrap your boilerplate\" --- Generic programming in Haskell +-- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. The present module+-- provides generic operations for text serialisation of terms.+--+-----------------------------------------------------------------------------++module Data.Generics.Text (++ -- * Generic show+ gshow, gshows,++ -- * Generic read+ gread++ ) where++------------------------------------------------------------------------------++#ifdef __HADDOCK__+import Prelude+#endif+import Control.Monad+import Data.Data+import Data.Generics.Aliases+import Text.ParserCombinators.ReadP+import Text.Read.Lex++------------------------------------------------------------------------------+++-- | Generic show: an alternative to \"deriving Show\"+gshow :: Data a => a -> String+gshow x = gshows x ""++-- | Generic shows+gshows :: Data a => a -> ShowS++-- This is a prefix-show using surrounding "(" and ")",+-- where we recurse into subterms with gmapQ.+gshows = ( \t ->+ showChar '('+ . (showString . showConstr . toConstr $ t)+ . (foldr (.) id . gmapQ ((showChar ' ' .) . gshows) $ t)+ . showChar ')'+ ) `extQ` (shows :: String -> ShowS)+++-- | Generic read: an alternative to \"deriving Read\"+gread :: Data a => ReadS a++{-++This is a read operation which insists on prefix notation. (The+Haskell 98 read deals with infix operators subject to associativity+and precedence as well.) We use fromConstrM to "parse" the input. To be+precise, fromConstrM is used for all types except String. The+type-specific case for String uses basic String read.++-}++gread = readP_to_S gread'++ where++ -- Helper for recursive read+ gread' :: Data a' => ReadP a'+ gread' = allButString `extR` stringCase++ where++ -- A specific case for strings+ stringCase :: ReadP String+ stringCase = readS_to_P reads++ -- Determine result type+ myDataType = dataTypeOf (getArg allButString)+ where+ getArg :: ReadP a'' -> a''+ getArg = undefined++ -- The generic default for gread+ allButString =+ do+ -- Drop " ( "+ skipSpaces -- Discard leading space+ _ <- char '(' -- Parse '('+ skipSpaces -- Discard following space++ -- Do the real work+ str <- parseConstr -- Get a lexeme for the constructor+ con <- str2con str -- Convert it to a Constr (may fail)+ x <- fromConstrM gread' con -- Read the children++ -- Drop " ) "+ skipSpaces -- Discard leading space+ _ <- char ')' -- Parse ')'+ skipSpaces -- Discard following space++ return x++ -- Turn string into constructor driven by the requested result type,+ -- failing in the monad if it isn't a constructor of this data type+ str2con :: String -> ReadP Constr+ str2con = maybe mzero return+ . readConstr myDataType++ -- Get a Constr's string at the front of an input string+ parseConstr :: ReadP String+ parseConstr =+ string "[]" -- Compound lexeme "[]"+ <++ string "()" -- singleton "()"+ <++ infixOp -- Infix operator in parantheses+ <++ hsLex -- Ordinary constructors and literals++ -- Handle infix operators such as (:)+ infixOp :: ReadP String+ infixOp = do c1 <- char '('+ str <- munch1 (not . (==) ')')+ c2 <- char ')'+ return $ [c1] ++ str ++ [c2]
src/Data/Generics/Twins.hs view
@@ -1,291 +1,294 @@-{-# LANGUAGE RankNTypes, ScopedTypeVariables, CPP #-} ------------------------------------------------------------------------------ --- | --- Module : Data.Generics.Twins --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- \"Scrap your boilerplate\" --- Generic programming in Haskell --- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. The present module --- provides support for multi-parameter traversal, which is also --- demonstrated with generic operations like equality. --- ------------------------------------------------------------------------------ - -module Data.Generics.Twins ( - - -- * Generic folds and maps that also accumulate - gfoldlAccum, - gmapAccumT, - gmapAccumM, - gmapAccumQl, - gmapAccumQr, - gmapAccumQ, - gmapAccumA, - - -- * Mapping combinators for twin traversal - gzipWithT, - gzipWithM, - gzipWithQ, - - -- * Typical twin traversals - geq, - gzip, - gcompare - - ) where - - ------------------------------------------------------------------------------- - -#ifdef __HADDOCK__ -import Prelude -#endif -import Data.Data -import Data.Generics.Aliases - -#ifdef __GLASGOW_HASKELL__ -import Prelude hiding ( GT ) -#endif - -#if __GLASGOW_HASKELL__ < 709 -import Control.Applicative (Applicative(..)) -import Data.Monoid ( mappend, mconcat ) -#endif - ------------------------------------------------------------------------------- - - ------------------------------------------------------------------------------- --- --- Generic folds and maps that also accumulate --- ------------------------------------------------------------------------------- - -{-------------------------------------------------------------- - -A list map can be elaborated to perform accumulation. -In the same sense, we can elaborate generic maps over terms. - -We recall the type of map: -map :: (a -> b) -> [a] -> [b] - -We recall the type of an accumulating map (see Data.List): -mapAccumL :: (a -> b -> (a,c)) -> a -> [b] -> (a,[c]) - -Applying the same scheme we obtain an accumulating gfoldl. - ---------------------------------------------------------------} - --- | gfoldl with accumulation - -gfoldlAccum :: Data d - => (forall e r. Data e => a -> c (e -> r) -> e -> (a, c r)) - -> (forall g. a -> g -> (a, c g)) - -> a -> d -> (a, c d) - -gfoldlAccum k z a0 d = unA (gfoldl k' z' d) a0 - where - k' c y = A (\a -> let (a', c') = unA c a in k a' c' y) - z' f = A (\a -> z a f) - - --- | A type constructor for accumulation -newtype A a c d = A { unA :: a -> (a, c d) } - - --- | gmapT with accumulation -gmapAccumT :: Data d - => (forall e. Data e => a -> e -> (a,e)) - -> a -> d -> (a, d) -gmapAccumT f a0 d0 = let (a1, d1) = gfoldlAccum k z a0 d0 - in (a1, unID d1) - where - k a (ID c) d = let (a',d') = f a d - in (a', ID (c d')) - z a x = (a, ID x) - - --- | Applicative version -gmapAccumA :: forall b d a. (Data d, Applicative a) - => (forall e. Data e => b -> e -> (b, a e)) - -> b -> d -> (b, a d) -gmapAccumA f a0 d0 = gfoldlAccum k z a0 d0 - where - k :: forall d' e. (Data d') => - b -> a (d' -> e) -> d' -> (b, a e) - k a c d = let (a',d') = f a d - c' = c <*> d' - in (a', c') - z :: forall t c a'. (Applicative a') => - t -> c -> (t, a' c) - z a x = (a, pure x) - - --- | gmapM with accumulation -gmapAccumM :: (Data d, Monad m) - => (forall e. Data e => a -> e -> (a, m e)) - -> a -> d -> (a, m d) -gmapAccumM f = gfoldlAccum k z - where - k a c d = let (a',d') = f a d - in (a', d' >>= \d'' -> c >>= \c' -> return (c' d'')) - z a x = (a, return x) - - --- | gmapQl with accumulation -gmapAccumQl :: Data d - => (r -> r' -> r) - -> r - -> (forall e. Data e => a -> e -> (a,r')) - -> a -> d -> (a, r) -gmapAccumQl o r0 f a0 d0 = let (a1, r1) = gfoldlAccum k z a0 d0 - in (a1, unCONST r1) - where - k a (CONST c) d = let (a', r) = f a d - in (a', CONST (c `o` r)) - z a _ = (a, CONST r0) - - --- | gmapQr with accumulation -gmapAccumQr :: Data d - => (r' -> r -> r) - -> r - -> (forall e. Data e => a -> e -> (a,r')) - -> a -> d -> (a, r) -gmapAccumQr o r0 f a0 d0 = let (a1, l) = gfoldlAccum k z a0 d0 - in (a1, unQr l r0) - where - k a (Qr c) d = let (a',r') = f a d - in (a', Qr (\r -> c (r' `o` r))) - z a _ = (a, Qr id) - - --- | gmapQ with accumulation -gmapAccumQ :: Data d - => (forall e. Data e => a -> e -> (a,q)) - -> a -> d -> (a, [q]) -gmapAccumQ f = gmapAccumQr (:) [] f - - - ------------------------------------------------------------------------------- --- --- Helper type constructors --- ------------------------------------------------------------------------------- - - --- | The identity type constructor needed for the definition of gmapAccumT -newtype ID x = ID { unID :: x } - - --- | The constant type constructor needed for the definition of gmapAccumQl -newtype CONST c a = CONST { unCONST :: c } - - --- | The type constructor needed for the definition of gmapAccumQr -newtype Qr r a = Qr { unQr :: r -> r } - - - ------------------------------------------------------------------------------- --- --- Mapping combinators for twin traversal --- ------------------------------------------------------------------------------- - - --- | Twin map for transformation -gzipWithT :: GenericQ (GenericT) -> GenericQ (GenericT) -gzipWithT f x y = case gmapAccumT perkid funs y of - ([], c) -> c - _ -> error "gzipWithT" - where - perkid a d = (tail a, unGT (head a) d) - funs = gmapQ (\k -> GT (f k)) x - - - --- | Twin map for monadic transformation -gzipWithM :: Monad m => GenericQ (GenericM m) -> GenericQ (GenericM m) -gzipWithM f x y = case gmapAccumM perkid funs y of - ([], c) -> c - _ -> error "gzipWithM" - where - perkid a d = (tail a, unGM (head a) d) - funs = gmapQ (\k -> GM (f k)) x - - --- | Twin map for queries -gzipWithQ :: GenericQ (GenericQ r) -> GenericQ (GenericQ [r]) -gzipWithQ f x y = case gmapAccumQ perkid funs y of - ([], r) -> r - _ -> error "gzipWithQ" - where - perkid a d = (tail a, unGQ (head a) d) - funs = gmapQ (\k -> GQ (f k)) x - - - ------------------------------------------------------------------------------- --- --- Typical twin traversals --- ------------------------------------------------------------------------------- - --- | Generic equality: an alternative to \"deriving Eq\" -geq :: Data a => a -> a -> Bool - -{- - -Testing for equality of two terms goes like this. Firstly, we -establish the equality of the two top-level datatype -constructors. Secondly, we use a twin gmap combinator, namely tgmapQ, -to compare the two lists of immediate subterms. - -(Note for the experts: the type of the worker geq' is rather general -but precision is recovered via the restrictive type of the top-level -operation geq. The imprecision of geq' is caused by the type system's -unability to express the type equivalence for the corresponding -couples of immediate subterms from the two given input terms.) - --} - -geq x0 y0 = geq' x0 y0 - where - geq' :: GenericQ (GenericQ Bool) - geq' x y = (toConstr x == toConstr y) - && and (gzipWithQ geq' x y) - - --- | Generic zip controlled by a function with type-specific branches -gzip :: GenericQ (GenericM Maybe) -> GenericQ (GenericM Maybe) --- See testsuite/.../Generics/gzip.hs for an illustration -gzip f x y = - f x y - `orElse` - if toConstr x == toConstr y - then gzipWithM (gzip f) x y - else Nothing - --- | Generic comparison: an alternative to \"deriving Ord\" -gcompare :: Data a => a -> a -> Ordering -gcompare = gcompare' - where - gcompare' :: (Data a, Data b) => a -> b -> Ordering - gcompare' x y - = let repX = constrRep $ toConstr x - repY = constrRep $ toConstr y - in - case (repX, repY) of - (AlgConstr nX, AlgConstr nY) -> - nX `compare` nY `mappend` mconcat (gzipWithQ gcompare' x y) - (IntConstr iX, IntConstr iY) -> iX `compare` iY - (FloatConstr rX, FloatConstr rY) -> rX `compare` rY - (CharConstr cX, CharConstr cY) -> cX `compare` cY - _ -> error "type incompatibility in gcompare" +{-# LANGUAGE RankNTypes, ScopedTypeVariables, CPP #-}+-----------------------------------------------------------------------------+-- |+-- Module : Data.Generics.Twins+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+--+-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- \"Scrap your boilerplate\" --- Generic programming in Haskell+-- See <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>. The present module+-- provides support for multi-parameter traversal, which is also+-- demonstrated with generic operations like equality.+--+-----------------------------------------------------------------------------++module Data.Generics.Twins (++ -- * Generic folds and maps that also accumulate+ gfoldlAccum,+ gmapAccumT,+ gmapAccumM,+ gmapAccumQl,+ gmapAccumQr,+ gmapAccumQ,+ gmapAccumA,++ -- * Mapping combinators for twin traversal+ gzipWithT,+ gzipWithM,+ gzipWithQ,++ -- * Typical twin traversals+ geq,+ gzip,+ gcompare++ ) where+++------------------------------------------------------------------------------++#ifdef __HADDOCK__+import Prelude+#endif+import Data.Data+import Data.Generics.Aliases++#ifdef __GLASGOW_HASKELL__+import Prelude hiding ( GT )+#endif++#if __GLASGOW_HASKELL__ < 709+import Control.Applicative (Applicative(..))+import Data.Monoid ( mappend, mconcat )+#endif++------------------------------------------------------------------------------+++------------------------------------------------------------------------------+--+-- Generic folds and maps that also accumulate+--+------------------------------------------------------------------------------++{--------------------------------------------------------------++A list map can be elaborated to perform accumulation.+In the same sense, we can elaborate generic maps over terms.++We recall the type of map:+map :: (a -> b) -> [a] -> [b]++We recall the type of an accumulating map (see Data.List):+mapAccumL :: (a -> b -> (a,c)) -> a -> [b] -> (a,[c])++Applying the same scheme we obtain an accumulating gfoldl.++--------------------------------------------------------------}++-- | gfoldl with accumulation++gfoldlAccum :: Data d+ => (forall e r. Data e => a -> c (e -> r) -> e -> (a, c r))+ -> (forall g. a -> g -> (a, c g))+ -> a -> d -> (a, c d)++gfoldlAccum k z a0 d = unA (gfoldl k' z' d) a0+ where+ k' c y = A (\a -> let (a', c') = unA c a in k a' c' y)+ z' f = A (\a -> z a f)+++-- | A type constructor for accumulation+newtype A a c d = A { unA :: a -> (a, c d) }+++-- | gmapT with accumulation+gmapAccumT :: Data d+ => (forall e. Data e => a -> e -> (a,e))+ -> a -> d -> (a, d)+gmapAccumT f a0 d0 = let (a1, d1) = gfoldlAccum k z a0 d0+ in (a1, unID d1)+ where+ k a (ID c) d = let (a',d') = f a d+ in (a', ID (c d'))+ z a x = (a, ID x)+++-- | Applicative version+gmapAccumA :: forall b d a. (Data d, Applicative a)+ => (forall e. Data e => b -> e -> (b, a e))+ -> b -> d -> (b, a d)+gmapAccumA f a0 d0 = gfoldlAccum k z a0 d0+ where+ k :: forall d' e. (Data d') =>+ b -> a (d' -> e) -> d' -> (b, a e)+ k a c d = let (a',d') = f a d+ c' = c <*> d'+ in (a', c')+ z :: forall t c a'. (Applicative a') =>+ t -> c -> (t, a' c)+ z a x = (a, pure x)+++-- | gmapM with accumulation+gmapAccumM :: (Data d, Monad m)+ => (forall e. Data e => a -> e -> (a, m e))+ -> a -> d -> (a, m d)+gmapAccumM f = gfoldlAccum k z+ where+ k a c d = let (a',d') = f a d+ in (a', d' >>= \d'' -> c >>= \c' -> return (c' d''))+ z a x = (a, return x)+++-- | gmapQl with accumulation+gmapAccumQl :: Data d+ => (r -> r' -> r)+ -> r+ -> (forall e. Data e => a -> e -> (a,r'))+ -> a -> d -> (a, r)+gmapAccumQl o r0 f a0 d0 = let (a1, r1) = gfoldlAccum k z a0 d0+ in (a1, unCONST r1)+ where+ k a (CONST c) d = let (a', r) = f a d+ in (a', CONST (c `o` r))+ z a _ = (a, CONST r0)+++-- | gmapQr with accumulation+gmapAccumQr :: Data d+ => (r' -> r -> r)+ -> r+ -> (forall e. Data e => a -> e -> (a,r'))+ -> a -> d -> (a, r)+gmapAccumQr o r0 f a0 d0 = let (a1, l) = gfoldlAccum k z a0 d0+ in (a1, unQr l r0)+ where+ k a (Qr c) d = let (a',r') = f a d+ in (a', Qr (\r -> c (r' `o` r)))+ z a _ = (a, Qr id)+++-- | gmapQ with accumulation+gmapAccumQ :: Data d+ => (forall e. Data e => a -> e -> (a,q))+ -> a -> d -> (a, [q])+gmapAccumQ f = gmapAccumQr (:) [] f++++------------------------------------------------------------------------------+--+-- Helper type constructors+--+------------------------------------------------------------------------------+++-- | The identity type constructor needed for the definition of gmapAccumT+newtype ID x = ID { unID :: x }+++-- | The constant type constructor needed for the definition of gmapAccumQl+newtype CONST c a = CONST { unCONST :: c }+++-- | The type constructor needed for the definition of gmapAccumQr+newtype Qr r a = Qr { unQr :: r -> r }++++------------------------------------------------------------------------------+--+-- Mapping combinators for twin traversal+--+------------------------------------------------------------------------------+++-- | Twin map for transformation+gzipWithT :: GenericQ (GenericT) -> GenericQ (GenericT)+gzipWithT f x y = case gmapAccumT perkid funs y of+ ([], c) -> c+ _ -> error "gzipWithT"+ where+ perkid a d = (tail a, unGT (head a) d)+ funs = gmapQ (\k -> GT (f k)) x++++-- | Twin map for monadic transformation+gzipWithM :: Monad m => GenericQ (GenericM m) -> GenericQ (GenericM m)+gzipWithM f x y = case gmapAccumM perkid funs y of+ ([], c) -> c+ _ -> error "gzipWithM"+ where+ perkid a d = (tail a, unGM (head a) d)+ funs = gmapQ (\k -> GM (f k)) x+++-- | Twin map for queries+gzipWithQ :: GenericQ (GenericQ r) -> GenericQ (GenericQ [r])+gzipWithQ f x y = case gmapAccumQ perkid funs y of+ ([], r) -> r+ _ -> error "gzipWithQ"+ where+ perkid a d = (tail a, unGQ (head a) d)+ funs = gmapQ (\k -> GQ (f k)) x++++------------------------------------------------------------------------------+--+-- Typical twin traversals+--+------------------------------------------------------------------------------++-- | Generic equality: an alternative to \"deriving Eq\"+geq :: Data a => a -> a -> Bool++{-++Testing for equality of two terms goes like this. Firstly, we+establish the equality of the two top-level datatype+constructors. Secondly, we use a twin gmap combinator, namely tgmapQ,+to compare the two lists of immediate subterms.++(Note for the experts: the type of the worker geq' is rather general+but precision is recovered via the restrictive type of the top-level+operation geq. The imprecision of geq' is caused by the type system's+unability to express the type equivalence for the corresponding+couples of immediate subterms from the two given input terms.)++-}++geq x0 y0 = geq' x0 y0+ where+ geq' :: GenericQ (GenericQ Bool)+ geq' x y = (toConstr x == toConstr y)+ && and (gzipWithQ geq' x y)+++-- | Generic zip controlled by a function with type-specific branches+gzip :: GenericQ (GenericM Maybe) -> GenericQ (GenericM Maybe)+-- See testsuite/.../Generics/gzip.hs for an illustration+gzip f = go+ where+ go :: GenericQ (GenericM Maybe)+ go x y =+ f x y+ `orElse`+ if toConstr x == toConstr y+ then gzipWithM go x y+ else Nothing++-- | Generic comparison: an alternative to \"deriving Ord\"+gcompare :: Data a => a -> a -> Ordering+gcompare = gcompare'+ where+ gcompare' :: (Data a, Data b) => a -> b -> Ordering+ gcompare' x y+ = let repX = constrRep $ toConstr x+ repY = constrRep $ toConstr y+ in+ case (repX, repY) of+ (AlgConstr nX, AlgConstr nY) ->+ nX `compare` nY `mappend` mconcat (gzipWithQ gcompare' x y)+ (IntConstr iX, IntConstr iY) -> iX `compare` iY+ (FloatConstr rX, FloatConstr rY) -> rX `compare` rY+ (CharConstr cX, CharConstr cY) -> cX `compare` cY+ _ -> error "type incompatibility in gcompare"
src/Generics/SYB.hs view
@@ -1,17 +1,17 @@------------------------------------------------------------------------------ --- | --- Module : Generics.SYB --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the file libraries/base/LICENSE) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- Convenience alias for "Data.Generics". --- ------------------------------------------------------------------------------ - -module Generics.SYB (module Data.Generics) where - -import Data.Generics +-----------------------------------------------------------------------------+-- |+-- Module : Generics.SYB+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the file libraries/base/LICENSE)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- Convenience alias for "Data.Generics".+--+-----------------------------------------------------------------------------++module Generics.SYB (module Data.Generics) where++import Data.Generics
src/Generics/SYB/Aliases.hs view
@@ -1,17 +1,17 @@------------------------------------------------------------------------------ --- | --- Module : Generics.SYB.Aliases --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- Convenience alias for "Data.Generics.Aliases". --- ------------------------------------------------------------------------------ - -module Generics.SYB.Aliases (module Data.Generics.Aliases) where - -import Data.Generics.Aliases +-----------------------------------------------------------------------------+-- |+-- Module : Generics.SYB.Aliases+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- Convenience alias for "Data.Generics.Aliases".+--+-----------------------------------------------------------------------------++module Generics.SYB.Aliases (module Data.Generics.Aliases) where++import Data.Generics.Aliases
src/Generics/SYB/Basics.hs view
@@ -1,17 +1,17 @@------------------------------------------------------------------------------ --- | --- Module : Generics.SYB.Basics --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- Convenience alias for "Data.Generics.Basics". --- ------------------------------------------------------------------------------ - -module Generics.SYB.Basics (module Data.Generics.Basics) where - -import Data.Generics.Basics +-----------------------------------------------------------------------------+-- |+-- Module : Generics.SYB.Basics+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- Convenience alias for "Data.Generics.Basics".+--+-----------------------------------------------------------------------------++module Generics.SYB.Basics (module Data.Generics.Basics) where++import Data.Generics.Basics
src/Generics/SYB/Builders.hs view
@@ -1,17 +1,17 @@------------------------------------------------------------------------------ --- | --- Module : Generics.SYB.Builders --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- Convenience alias for "Data.Generics.Builders". --- ------------------------------------------------------------------------------ - -module Generics.SYB.Builders (module Data.Generics.Builders) where - -import Data.Generics.Builders +-----------------------------------------------------------------------------+-- |+-- Module : Generics.SYB.Builders+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- Convenience alias for "Data.Generics.Builders".+--+-----------------------------------------------------------------------------++module Generics.SYB.Builders (module Data.Generics.Builders) where++import Data.Generics.Builders
src/Generics/SYB/Instances.hs view
@@ -1,17 +1,17 @@------------------------------------------------------------------------------ --- | --- Module : Generics.SYB.Instances --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- Convenience alias for "Data.Generics.Instances". --- ------------------------------------------------------------------------------ - -module Generics.SYB.Instances () where - -import Data.Generics.Instances () +-----------------------------------------------------------------------------+-- |+-- Module : Generics.SYB.Instances+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- Convenience alias for "Data.Generics.Instances".+--+-----------------------------------------------------------------------------++module Generics.SYB.Instances () where++import Data.Generics.Instances ()
src/Generics/SYB/Schemes.hs view
@@ -1,17 +1,17 @@------------------------------------------------------------------------------ --- | --- Module : Generics.SYB.Schemes --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- Convenience alias for "Data.Generics.Schemes". --- ------------------------------------------------------------------------------ - -module Generics.SYB.Schemes (module Data.Generics.Schemes) where - -import Data.Generics.Schemes +-----------------------------------------------------------------------------+-- |+-- Module : Generics.SYB.Schemes+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- Convenience alias for "Data.Generics.Schemes".+--+-----------------------------------------------------------------------------++module Generics.SYB.Schemes (module Data.Generics.Schemes) where++import Data.Generics.Schemes
src/Generics/SYB/Text.hs view
@@ -1,17 +1,17 @@------------------------------------------------------------------------------ --- | --- Module : Generics.SYB.Text --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- Convenience alias for "Data.Generics.Text". --- ------------------------------------------------------------------------------ - -module Generics.SYB.Text (module Data.Generics.Text) where - -import Data.Generics.Text +-----------------------------------------------------------------------------+-- |+-- Module : Generics.SYB.Text+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- Convenience alias for "Data.Generics.Text".+--+-----------------------------------------------------------------------------++module Generics.SYB.Text (module Data.Generics.Text) where++import Data.Generics.Text
src/Generics/SYB/Twins.hs view
@@ -1,17 +1,17 @@------------------------------------------------------------------------------ --- | --- Module : Generics.SYB.Twins --- Copyright : (c) The University of Glasgow, CWI 2001--2004 --- License : BSD-style (see the LICENSE file) --- --- Maintainer : generics@haskell.org --- Stability : experimental --- Portability : non-portable (local universal quantification) --- --- Convenience alias for "Data.Generics.Twins". --- ------------------------------------------------------------------------------ - -module Generics.SYB.Twins (module Data.Generics.Twins) where - -import Data.Generics.Twins +-----------------------------------------------------------------------------+-- |+-- Module : Generics.SYB.Twins+-- Copyright : (c) The University of Glasgow, CWI 2001--2004+-- License : BSD-style (see the LICENSE file)+-- +-- Maintainer : generics@haskell.org+-- Stability : experimental+-- Portability : non-portable (local universal quantification)+--+-- Convenience alias for "Data.Generics.Twins".+--+-----------------------------------------------------------------------------++module Generics.SYB.Twins (module Data.Generics.Twins) where++import Data.Generics.Twins
syb.cabal view
@@ -1,65 +1,66 @@-name: syb -version: 0.7 -license: BSD3 -license-file: LICENSE -author: Ralf Lammel, Simon Peyton Jones, Jose Pedro Magalhaes -maintainer: generics@haskell.org -homepage: http://www.cs.uu.nl/wiki/GenericProgramming/SYB -bug-reports: http://code.google.com/p/scrapyourboilerplate/issues/list -synopsis: Scrap Your Boilerplate -description: - This package contains the generics system described in the - /Scrap Your Boilerplate/ papers (see - <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>). - It defines the @Data@ class of types permitting folding and unfolding - of constructor applications, instances of this class for primitive - types, and a variety of traversals. - -category: Generics -stability: provisional -build-type: Simple -cabal-version: >= 1.8 -tested-with: GHC >=7.0 && <=7.10.2, GHC==7.11.* - -extra-source-files: tests/*.hs, - README - -source-repository head - type: git - location: https://github.com/dreixel/syb - -Library - hs-source-dirs: src - build-depends: base >= 4.0 && < 5.0 - exposed-modules: Data.Generics, - Data.Generics.Basics, - Data.Generics.Instances, - Data.Generics.Aliases, - Data.Generics.Schemes, - Data.Generics.Text, - Data.Generics.Twins, - Data.Generics.Builders, - - Generics.SYB, - Generics.SYB.Basics, - Generics.SYB.Instances, - Generics.SYB.Aliases, - Generics.SYB.Schemes, - Generics.SYB.Text, - Generics.SYB.Twins, - Generics.SYB.Builders - - if impl(ghc < 6.12) - ghc-options: -package-name syb - - ghc-options: -Wall - -test-suite unit-tests - type: exitcode-stdio-1.0 - hs-source-dirs: tests - main-is: Main.hs - build-depends: base - , syb - , HUnit - , containers - , mtl +name: syb+version: 0.7.1+license: BSD3+license-file: LICENSE+author: Ralf Lammel, Simon Peyton Jones, Jose Pedro Magalhaes+maintainer: Sergey Vinokurov <serg.foo@gmail.com>+homepage: http://www.cs.uu.nl/wiki/GenericProgramming/SYB+bug-reports: https://github.com/dreixel/syb/issues+synopsis: Scrap Your Boilerplate+description:+ This package contains the generics system described in the+ /Scrap Your Boilerplate/ papers (see+ <http://www.cs.uu.nl/wiki/GenericProgramming/SYB>).+ It defines the @Data@ class of types permitting folding and unfolding+ of constructor applications, instances of this class for primitive+ types, and a variety of traversals.++category: Generics+stability: provisional+build-type: Simple+cabal-version: >= 1.8+tested-with: GHC >=7.0 && <=7.10.2, GHC==7.11.*, GHC==8.0, GHC==8.2, GHC==8.4.4, GHC==8.6.5++extra-source-files: tests/*.hs,+ README.md,+ ChangeLog++source-repository head+ type: git+ location: https://github.com/dreixel/syb++Library+ hs-source-dirs: src+ build-depends: base >= 4.0 && < 5.0+ exposed-modules: Data.Generics,+ Data.Generics.Basics,+ Data.Generics.Instances,+ Data.Generics.Aliases,+ Data.Generics.Schemes,+ Data.Generics.Text,+ Data.Generics.Twins,+ Data.Generics.Builders,++ Generics.SYB,+ Generics.SYB.Basics,+ Generics.SYB.Instances,+ Generics.SYB.Aliases,+ Generics.SYB.Schemes,+ Generics.SYB.Text,+ Generics.SYB.Twins,+ Generics.SYB.Builders++ if impl(ghc < 6.12)+ ghc-options: -package-name syb++ ghc-options: -Wall++test-suite unit-tests+ type: exitcode-stdio-1.0+ hs-source-dirs: tests+ main-is: Main.hs+ build-depends: base+ , syb+ , HUnit+ , containers+ , mtl
tests/Bits.hs view
@@ -1,225 +1,225 @@-{-# OPTIONS -fglasgow-exts #-} - -module Bits (tests) where - -{- - -This test exercices some oldies of generic programming, namely -encoding terms as bit streams and decoding these bit streams in turn -to obtain terms again. (This sort of function might actually be useful -for serialisation and sending companies and other terms over the -internet.) - -Here is how it works. - -A constuctor is encoded as a bit stream. To this end, we encode the -index of the constructor as a binary number of a fixed length taking -into account the maximum index for the type at hand. (Similarly, we -could view the list of constructors as a binary tree, and then encode -a constructor as the path to the constructor in this tree.) If there -is just a single constructor, as for newtypes, for example, then the -computed bit stream is empty. - -Otherwise we just recurse into subterms. - -Well, we need to handle basic datatypes in a special way. We observe -such basic datatypes by testing the maximum index to be 0 for the -datatype at hand. An efficient encoding should be tuned per basic -datatype. The following solution is generic, but it wastes space. -That is, we turn the basic value into a string relying on the general -Data API. This string can now be encoded by first converting it into a -list of bit streams at the term level, which can then be easily -encoded as a single bit stream (because lists and bits can be -encoded). - --} - -import Test.HUnit - -import Data.Generics -import Data.Char -import Data.Maybe -import Control.Applicative (Alternative(..), Applicative(..)) -import Control.Monad -import CompanyDatatypes - - - ------------------------------------------------------------------------------ - - - --- | We need bits and bit streams. -data Bit = Zero | One deriving (Show, Eq, Typeable, Data) -type Bin = [Bit] - - - ------------------------------------------------------------------------------ - - - --- Compute length of bit stream for a natural -lengthNat :: Int -> Int -lengthNat x = ceiling (logBase 2 (fromIntegral (x + 1))) - - --- Encode a natural as a bit stream -varNat2bin :: Int -> Bin -varNat2bin 0 = [] -varNat2bin x = - ( ( if even x then Zero else One ) - : varNat2bin (x `div` 2) - ) - - --- Encode a natural as a bit stream of fixed length -fixedNat2bin :: Int -> Int -> Bin -fixedNat2bin 0 0 = [] -fixedNat2bin p x | p>0 = - ( ( if even x then Zero else One ) - : fixedNat2bin (p - 1) (x `div` 2) - ) - - --- Decode a natural -bin2nat :: Bin -> Int -bin2nat [] = 0 -bin2nat (Zero : bs) = 2 * (bin2nat bs) -bin2nat (One : bs) = 2 * (bin2nat bs) + 1 - - - ------------------------------------------------------------------------------ - - - --- | Generically map terms to bit streams -showBin :: Data t => t -> Bin - -showBin t - = if isAlgType myDataType - then con2bin ++ concat (gmapQ showBin t) - else showBin base - - where - - -- The datatype for introspection - myDataType = dataTypeOf t - - -- Obtain the maximum index for the type at hand - max :: Int - max = maxConstrIndex myDataType - - -- Obtain the index for the constructor at hand - idx :: Int - idx = constrIndex (toConstr t) - - -- Map basic values to strings, then to lists of bit streams - base = map (varNat2bin . ord) (showConstr (toConstr t)) - - -- Map constructors to bit streams of fixed length - con2bin = fixedNat2bin (lengthNat (max - 1)) (idx - 1) - - ------------------------------------------------------------------------------ - - - --- | A monad on bit streams -data ReadB a = ReadB (Bin -> (Maybe a, Bin)) -unReadB (ReadB f) = f - -instance Functor ReadB where - fmap = liftM - -instance Applicative ReadB where - pure = return - (<*>) = ap - -instance Alternative ReadB where - (<|>) = mplus - empty = mzero - --- It's a monad. -instance Monad ReadB where - return a = ReadB (\bs -> (Just a, bs)) - (ReadB c) >>= f = ReadB (\bs -> case c bs of - (Just a, bs') -> unReadB (f a) bs' - (Nothing, bs') -> (Nothing, bs') - ) - - --- It's a bit monad with 0 and +. -instance MonadPlus ReadB where - mzero = ReadB (\bs -> (Nothing, bs)) - (ReadB f) `mplus` (ReadB g) = ReadB (\bs -> case f bs of - (Just a, bs') -> (Just a, bs') - (Nothing, _) -> g bs - ) - - --- Read a few bits -readB :: Int -> ReadB Bin -readB x = ReadB (\bs -> if length bs >= x - then (Just (take x bs), drop x bs) - else (Nothing, bs) - ) - - - ------------------------------------------------------------------------------ - - - --- | Generically map bit streams to terms -readBin :: Data t => ReadB t -readBin = result - where - - -- The worker, which we also use as type argument - result = if isAlgType myDataType - - then do bin <- readB (lengthNat (max - 1)) - fromConstrM readBin (bin2con bin) - - else do str <- readBin - con <- str2con (map (chr . bin2nat) str) - return (fromConstr con) - - -- Determine result type - myDataType = dataTypeOf (getArg result) - where - getArg :: ReadB a -> a - getArg = undefined - - -- Obtain the maximum index for the type at hand - max :: Int - max = maxConstrIndex myDataType - - -- Convert a bit stream into a constructor - bin2con :: Bin -> Constr - bin2con bin = indexConstr myDataType ((bin2nat bin) + 1) - - -- Convert string to constructor; could fail - str2con :: String -> ReadB Constr - str2con = maybe mzero return - . readConstr myDataType - - - ------------------------------------------------------------------------------ - - - -tests = ( showBin True - , ( showBin [True] - , ( showBin (1::Int) - , ( showBin "1" - , ( showBin genCom - , ( geq genCom genCom' - )))))) ~=? output - where - genCom' = fromJust (fst (unReadB readBin (showBin genCom))) :: Company - -output = 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+{-# OPTIONS -fglasgow-exts #-}++module Bits (tests) where++{-+ +This test exercices some oldies of generic programming, namely+encoding terms as bit streams and decoding these bit streams in turn+to obtain terms again. (This sort of function might actually be useful+for serialisation and sending companies and other terms over the+internet.)++Here is how it works.++A constuctor is encoded as a bit stream. To this end, we encode the+index of the constructor as a binary number of a fixed length taking+into account the maximum index for the type at hand. (Similarly, we+could view the list of constructors as a binary tree, and then encode+a constructor as the path to the constructor in this tree.) If there+is just a single constructor, as for newtypes, for example, then the+computed bit stream is empty.++Otherwise we just recurse into subterms.++Well, we need to handle basic datatypes in a special way. We observe+such basic datatypes by testing the maximum index to be 0 for the+datatype at hand. An efficient encoding should be tuned per basic+datatype. The following solution is generic, but it wastes space.+That is, we turn the basic value into a string relying on the general+Data API. This string can now be encoded by first converting it into a+list of bit streams at the term level, which can then be easily+encoded as a single bit stream (because lists and bits can be+encoded).++-}++import Test.HUnit++import Data.Generics+import Data.Char+import Data.Maybe+import Control.Applicative (Alternative(..), Applicative(..))+import Control.Monad+import CompanyDatatypes++++-----------------------------------------------------------------------------++++-- | We need bits and bit streams.+data Bit = Zero | One deriving (Show, Eq, Typeable, Data)+type Bin = [Bit]++++-----------------------------------------------------------------------------++++-- Compute length of bit stream for a natural+lengthNat :: Int -> Int+lengthNat x = ceiling (logBase 2 (fromIntegral (x + 1)))+++-- Encode a natural as a bit stream+varNat2bin :: Int -> Bin+varNat2bin 0 = []+varNat2bin x =+ ( ( if even x then Zero else One )+ : varNat2bin (x `div` 2)+ ) +++-- Encode a natural as a bit stream of fixed length+fixedNat2bin :: Int -> Int -> Bin+fixedNat2bin 0 0 = []+fixedNat2bin p x | p>0 =+ ( ( if even x then Zero else One )+ : fixedNat2bin (p - 1) (x `div` 2)+ ) +++-- Decode a natural+bin2nat :: Bin -> Int+bin2nat [] = 0+bin2nat (Zero : bs) = 2 * (bin2nat bs)+bin2nat (One : bs) = 2 * (bin2nat bs) + 1++++-----------------------------------------------------------------------------++++-- | Generically map terms to bit streams+showBin :: Data t => t -> Bin++showBin t+ = if isAlgType myDataType+ then con2bin ++ concat (gmapQ showBin t)+ else showBin base++ where++ -- The datatype for introspection+ myDataType = dataTypeOf t++ -- Obtain the maximum index for the type at hand+ max :: Int+ max = maxConstrIndex myDataType++ -- Obtain the index for the constructor at hand+ idx :: Int+ idx = constrIndex (toConstr t)++ -- Map basic values to strings, then to lists of bit streams+ base = map (varNat2bin . ord) (showConstr (toConstr t))++ -- Map constructors to bit streams of fixed length+ con2bin = fixedNat2bin (lengthNat (max - 1)) (idx - 1)+++-----------------------------------------------------------------------------++++-- | A monad on bit streams+data ReadB a = ReadB (Bin -> (Maybe a, Bin))+unReadB (ReadB f) = f++instance Functor ReadB where+ fmap = liftM++instance Applicative ReadB where+ pure = return+ (<*>) = ap++instance Alternative ReadB where+ (<|>) = mplus+ empty = mzero++-- It's a monad.+instance Monad ReadB where+ return a = ReadB (\bs -> (Just a, bs))+ (ReadB c) >>= f = ReadB (\bs -> case c bs of+ (Just a, bs') -> unReadB (f a) bs'+ (Nothing, bs') -> (Nothing, bs')+ )+++-- It's a bit monad with 0 and +.+instance MonadPlus ReadB where+ mzero = ReadB (\bs -> (Nothing, bs))+ (ReadB f) `mplus` (ReadB g) = ReadB (\bs -> case f bs of+ (Just a, bs') -> (Just a, bs')+ (Nothing, _) -> g bs+ )+++-- Read a few bits+readB :: Int -> ReadB Bin+readB x = ReadB (\bs -> if length bs >= x+ then (Just (take x bs), drop x bs)+ else (Nothing, bs)+ )++++-----------------------------------------------------------------------------++++-- | Generically map bit streams to terms+readBin :: Data t => ReadB t+readBin = result+ where++ -- The worker, which we also use as type argument+ result = if isAlgType myDataType++ then do bin <- readB (lengthNat (max - 1))+ fromConstrM readBin (bin2con bin)++ else do str <- readBin+ con <- str2con (map (chr . bin2nat) str)+ return (fromConstr con)++ -- Determine result type+ myDataType = dataTypeOf (getArg result)+ where+ getArg :: ReadB a -> a+ getArg = undefined++ -- Obtain the maximum index for the type at hand+ max :: Int+ max = maxConstrIndex myDataType++ -- Convert a bit stream into a constructor + bin2con :: Bin -> Constr+ bin2con bin = indexConstr myDataType ((bin2nat bin) + 1)++ -- Convert string to constructor; could fail+ str2con :: String -> ReadB Constr+ str2con = maybe mzero return+ . readConstr myDataType++++-----------------------------------------------------------------------------++++tests = ( showBin True+ , ( showBin [True]+ , ( showBin (1::Int)+ , ( showBin "1"+ , ( showBin genCom+ , ( geq genCom genCom' + )))))) ~=? output+ where+ genCom' = fromJust (fst (unReadB readBin (showBin genCom))) :: Company++output = 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tests/Builders.hs view
@@ -1,20 +1,20 @@-{-# OPTIONS -fglasgow-exts #-} - -module Builders (tests) where - --- Testing Data.Generics.Builders functionality - -import Test.HUnit - -import Data.Data -import Data.Generics.Builders - - --- Main function for testing -tests = ( constrs :: [Maybe Int] - , constrs :: [String] - , constrs :: [Either Int Float] - , constrs :: [((), Integer)] - ) ~=? output - +{-# OPTIONS -fglasgow-exts #-}++module Builders (tests) where++-- Testing Data.Generics.Builders functionality ++import Test.HUnit++import Data.Data+import Data.Generics.Builders+++-- Main function for testing+tests = ( constrs :: [Maybe Int]+ , constrs :: [String]+ , constrs :: [Either Int Float]+ , constrs :: [((), Integer)]+ ) ~=? output+ output = ([Nothing,Just 0],["","\NUL"],[Left 0,Right 0.0],[((),0)])
tests/CompanyDatatypes.hs view
@@ -1,39 +1,39 @@-{-# OPTIONS -fglasgow-exts #-} - -module CompanyDatatypes where - -import Data.Generics (Data, Typeable) - --- The organisational structure of a company - -data Company = C [Dept] deriving (Eq, Show, Typeable, Data) -data Dept = D Name Manager [Unit] deriving (Eq, Show, Typeable, Data) -data Unit = PU Employee | DU Dept deriving (Eq, Show, Typeable, Data) -data Employee = E Person Salary deriving (Eq, Show, Typeable, Data) -data Person = P Name Address deriving (Eq, Show, Typeable, Data) -data Salary = S Float deriving (Eq, Show, Typeable, Data) -type Manager = Employee -type Name = String -type Address = String - --- An illustrative company -genCom :: Company -genCom = C [D "Research" laemmel [PU joost, PU marlow], - D "Strategy" blair []] - --- A typo for the sake of testing equality; --- (cf. lammel vs. laemmel) -genCom' :: Company -genCom' = C [D "Research" lammel [PU joost, PU marlow], - D "Strategy" blair []] - -lammel, laemmel, joost, marlow, blair :: Employee -lammel = E (P "Lammel" "Amsterdam") (S 8000) -laemmel = E (P "Laemmel" "Amsterdam") (S 8000) -joost = E (P "Joost" "Amsterdam") (S 1000) -marlow = E (P "Marlow" "Cambridge") (S 2000) -blair = E (P "Blair" "London") (S 100000) - --- Some more test data -person1 = P "Lazy" "Home" -dept1 = D "Useless" (E person1 undefined) [] +{-# OPTIONS -fglasgow-exts #-}++module CompanyDatatypes where++import Data.Generics (Data, Typeable)++-- The organisational structure of a company++data Company = C [Dept] deriving (Eq, Show, Typeable, Data)+data Dept = D Name Manager [Unit] deriving (Eq, Show, Typeable, Data)+data Unit = PU Employee | DU Dept deriving (Eq, Show, Typeable, Data)+data Employee = E Person Salary deriving (Eq, Show, Typeable, Data)+data Person = P Name Address deriving (Eq, Show, Typeable, Data)+data Salary = S Float deriving (Eq, Show, Typeable, Data)+type Manager = Employee+type Name = String+type Address = String++-- An illustrative company+genCom :: Company+genCom = C [D "Research" laemmel [PU joost, PU marlow],+ D "Strategy" blair []]++-- A typo for the sake of testing equality;+-- (cf. lammel vs. laemmel)+genCom' :: Company+genCom' = C [D "Research" lammel [PU joost, PU marlow],+ D "Strategy" blair []]++lammel, laemmel, joost, marlow, blair :: Employee+lammel = E (P "Lammel" "Amsterdam") (S 8000)+laemmel = E (P "Laemmel" "Amsterdam") (S 8000)+joost = E (P "Joost" "Amsterdam") (S 1000)+marlow = E (P "Marlow" "Cambridge") (S 2000)+blair = E (P "Blair" "London") (S 100000)++-- Some more test data+person1 = P "Lazy" "Home"+dept1 = D "Useless" (E person1 undefined) []
tests/Datatype.hs view
@@ -1,55 +1,55 @@-{-# LANGUAGE CPP #-} -{-# OPTIONS -fglasgow-exts #-} - --- These are simple tests to observe (data)type representations. -module Datatype where - -import Test.HUnit - -import Data.Tree -import Data.Generics - --- A simple polymorphic datatype -data MyDataType a = MyDataType a - deriving (Typeable, Data) - - --- Some terms and corresponding type representations -myTerm = undefined :: MyDataType Int -myTypeRep = typeOf myTerm -- type representation in Typeable -myDataType = dataTypeOf myTerm -- datatype representation in Data - -#if MIN_VERSION_base(4,5,0) -myTyCon = typeRepTyCon myTypeRep -- type constructor via Typeable -myString1 = tyConName myTyCon -- type constructor via Typeable -myString2 = dataTypeName myDataType -- type constructor via Data - --- Main function for testing -tests = show ( myTypeRep - , ( myDataType - , ( tyconModule myString1 - , ( tyconUQname myString1 - , ( tyconModule myString2 - , ( tyconUQname myString2 - )))))) - ~?= output - -#if __GLASGOW_HASKELL__ >= 709 --- In GHC 7.10 module name is stripped from DataType -output = "(MyDataType Int,(DataType {tycon = \"MyDataType\", datarep = AlgRep [MyDataType]},(\"\",(\"MyDataType\",(\"\",\"MyDataType\")))))" -#else -output = "(MyDataType Int,(DataType {tycon = \"Datatype.MyDataType\", datarep = AlgRep [MyDataType]},(\"\",(\"MyDataType\",(\"Datatype\",\"MyDataType\")))))" -#endif - -#else - -tests = show ( myTypeRep, myDataType ) - ~?= output - -#if __GLASGOW_HASKELL__ >= 701 -output = "(MyDataType Int,DataType {tycon = \"Datatype.MyDataType\", datarep = AlgRep [MyDataType]})" -#else -output = "(Datatype.MyDataType Int,DataType {tycon = \"Datatype.MyDataType\", datarep = AlgRep [MyDataType]})" -#endif - -#endif +{-# LANGUAGE CPP #-}+{-# OPTIONS -fglasgow-exts #-}++-- These are simple tests to observe (data)type representations.+module Datatype where++import Test.HUnit++import Data.Tree+import Data.Generics++-- A simple polymorphic datatype+data MyDataType a = MyDataType a+ deriving (Typeable, Data)+++-- Some terms and corresponding type representations+myTerm = undefined :: MyDataType Int+myTypeRep = typeOf myTerm -- type representation in Typeable+myDataType = dataTypeOf myTerm -- datatype representation in Data++#if MIN_VERSION_base(4,5,0)+myTyCon = typeRepTyCon myTypeRep -- type constructor via Typeable+myString1 = tyConName myTyCon -- type constructor via Typeable+myString2 = dataTypeName myDataType -- type constructor via Data++-- Main function for testing+tests = show ( myTypeRep+ , ( myDataType+ , ( tyconModule myString1+ , ( tyconUQname myString1+ , ( tyconModule myString2+ , ( tyconUQname myString2+ ))))))+ ~?= output++#if __GLASGOW_HASKELL__ >= 709+-- In GHC 7.10 module name is stripped from DataType+output = "(MyDataType Int,(DataType {tycon = \"MyDataType\", datarep = AlgRep [MyDataType]},(\"\",(\"MyDataType\",(\"\",\"MyDataType\")))))"+#else+output = "(MyDataType Int,(DataType {tycon = \"Datatype.MyDataType\", datarep = AlgRep [MyDataType]},(\"\",(\"MyDataType\",(\"Datatype\",\"MyDataType\")))))"+#endif++#else++tests = show ( myTypeRep, myDataType )+ ~?= output++#if __GLASGOW_HASKELL__ >= 701+output = "(MyDataType Int,DataType {tycon = \"Datatype.MyDataType\", datarep = AlgRep [MyDataType]})"+#else+output = "(Datatype.MyDataType Int,DataType {tycon = \"Datatype.MyDataType\", datarep = AlgRep [MyDataType]})"+#endif++#endif
tests/Encode.hs view
@@ -1,88 +1,88 @@-{-# OPTIONS -fglasgow-exts #-} - --- A bit more test code for the 2nd boilerplate paper. --- These are downscaled versions of library functionality or real test cases. --- We just wanted to typecheck the fragments as shown in the paper. - -module Encode () where - -import Control.Applicative (Applicative(..)) -import Control.Monad (ap, liftM) -import Data.Generics - -data Bit = Zero | One - ------------------------------------------------------------------------------- --- Sec. 3.2 - -data2bits :: Data a => a -> [Bit] -data2bits t = encodeCon (dataTypeOf t) (toConstr t) - ++ concat (gmapQ data2bits t) - --- The encoder for constructors -encodeCon :: DataType -> Constr -> [Bit] -encodeCon ty con = natToBin (max-1) (idx-1) - where - max = maxConstrIndex ty - idx = constrIndex con - - -natToBin :: Int -> Int -> [Bit] -natToBin = undefined - ------------------------------------------------------------------------------- --- Sec. 3.3 - -data State -- Abstract -initState :: State -encodeCon' :: DataType -> Constr - -> State -> (State, [Bit]) - -initState = undefined -encodeCon' = undefined - -data2bits' :: Data a => a -> [Bit] -data2bits' t = snd (show_bin t initState) - -show_bin :: Data a => a -> State -> (State, [Bit]) -show_bin t st = (st2, con_bits ++ args_bits) - where - (st1, con_bits) = encodeCon' (dataTypeOf t) - (toConstr t) st - (st2, args_bits) = foldr do_arg (st1,[]) - enc_args - - enc_args :: [State -> (State,[Bit])] - enc_args = gmapQ show_bin t - - do_arg fn (st,bits) = (st', bits' ++ bits) - where - (st', bits') = fn st - - ------------------------------------------------------------------------------- --- Sec. 3.3 cont'd - -data EncM a -- The encoder monad -instance Functor EncM where - fmap = liftM -instance Applicative EncM where - pure = return - (<*>) = ap -instance Monad EncM - where - return = undefined - c >>= f = undefined - -runEnc :: EncM () -> [Bit] -emitCon :: DataType -> Constr -> EncM () - -runEnc = undefined -emitCon = undefined - -data2bits'' :: Data a => a -> [Bit] -data2bits'' t = runEnc (emit t) - -emit :: Data a => a -> EncM () -emit t = do { emitCon (dataTypeOf t) (toConstr t) - ; sequence_ (gmapQ emit t) } +{-# OPTIONS -fglasgow-exts #-}++-- A bit more test code for the 2nd boilerplate paper.+-- These are downscaled versions of library functionality or real test cases.+-- We just wanted to typecheck the fragments as shown in the paper.++module Encode () where++import Control.Applicative (Applicative(..))+import Control.Monad (ap, liftM)+import Data.Generics++data Bit = Zero | One++------------------------------------------------------------------------------+-- Sec. 3.2++data2bits :: Data a => a -> [Bit]+data2bits t = encodeCon (dataTypeOf t) (toConstr t)+ ++ concat (gmapQ data2bits t)++-- The encoder for constructors+encodeCon :: DataType -> Constr -> [Bit]+encodeCon ty con = natToBin (max-1) (idx-1)+ where+ max = maxConstrIndex ty+ idx = constrIndex con+++natToBin :: Int -> Int -> [Bit]+natToBin = undefined++------------------------------------------------------------------------------+-- Sec. 3.3++data State -- Abstract+initState :: State+encodeCon' :: DataType -> Constr+ -> State -> (State, [Bit])++initState = undefined+encodeCon' = undefined++data2bits' :: Data a => a -> [Bit]+data2bits' t = snd (show_bin t initState)++show_bin :: Data a => a -> State -> (State, [Bit])+show_bin t st = (st2, con_bits ++ args_bits)+ where+ (st1, con_bits) = encodeCon' (dataTypeOf t)+ (toConstr t) st+ (st2, args_bits) = foldr do_arg (st1,[])+ enc_args++ enc_args :: [State -> (State,[Bit])]+ enc_args = gmapQ show_bin t++ do_arg fn (st,bits) = (st', bits' ++ bits)+ where+ (st', bits') = fn st+++------------------------------------------------------------------------------+-- Sec. 3.3 cont'd++data EncM a -- The encoder monad+instance Functor EncM where+ fmap = liftM+instance Applicative EncM where+ pure = return+ (<*>) = ap+instance Monad EncM+ where+ return = undefined+ c >>= f = undefined++runEnc :: EncM () -> [Bit]+emitCon :: DataType -> Constr -> EncM ()++runEnc = undefined+emitCon = undefined++data2bits'' :: Data a => a -> [Bit]+data2bits'' t = runEnc (emit t)++emit :: Data a => a -> EncM ()+emit t = do { emitCon (dataTypeOf t) (toConstr t) + ; sequence_ (gmapQ emit t) }
tests/Ext.hs view
@@ -1,30 +1,30 @@-{-# OPTIONS -fglasgow-exts #-} - -module Ext () where - --- There were typos in these definitions in the ICFP 2004 paper. - -import Data.Generics - -extQ fn spec_fn arg - = case gcast (Q spec_fn) of - Just (Q spec_fn') -> spec_fn' arg - Nothing -> fn arg - -newtype Q r a = Q (a -> r) - -extT fn spec_fn arg - = case gcast (T spec_fn) of - Just (T spec_fn') -> spec_fn' arg - Nothing -> fn arg - -newtype T a = T (a -> a) - -extM :: (Typeable a, Typeable b) - => (a -> m a) -> (b -> m b) -> (a -> m a) -extM fn spec_fn - = case gcast (M spec_fn) of - Just (M spec_fn') -> spec_fn' - Nothing -> fn - -newtype M m a = M (a -> m a) +{-# OPTIONS -fglasgow-exts #-}++module Ext () where++-- There were typos in these definitions in the ICFP 2004 paper.++import Data.Generics++extQ fn spec_fn arg+ = case gcast (Q spec_fn) of+ Just (Q spec_fn') -> spec_fn' arg+ Nothing -> fn arg+ +newtype Q r a = Q (a -> r)+ +extT fn spec_fn arg+ = case gcast (T spec_fn) of+ Just (T spec_fn') -> spec_fn' arg+ Nothing -> fn arg+ +newtype T a = T (a -> a)++extM :: (Typeable a, Typeable b)+ => (a -> m a) -> (b -> m b) -> (a -> m a)+extM fn spec_fn+ = case gcast (M spec_fn) of+ Just (M spec_fn') -> spec_fn'+ Nothing -> fn++newtype M m a = M (a -> m a)
tests/Ext1.hs view
@@ -1,128 +1,128 @@-{-# OPTIONS -fglasgow-exts #-} -{-# LANGUAGE CPP #-} - -module Ext1 (tests) where - -{- - -This example records some experiments with polymorphic datatypes. - --} - -import Test.HUnit - -import Data.Generics -#if MIN_VERSION_base(4,8,0) -import GHC.Base hiding(foldr) -#else -import GHC.Base -#endif - --- Unsafe coerce -unsafeCoerce :: a -> b -unsafeCoerce = unsafeCoerce# - - --- Handy type constructors -newtype ID x = ID { unID :: x } -newtype CONST c a = CONST { unCONST :: c } - - --- Extension of a query with a para. poly. list case -extListQ' :: Data d - => (d -> q) - -> (forall d. [d] -> q) - -> d -> q -extListQ' def ext d = - if isList d - then ext (unsafeCoerce d) - else def d - - --- Test extListQ' -foo1 :: Data d => d -> Int -foo1 = const 0 `extListQ'` length -t1 = foo1 True -- should count as 0 -t2 = foo1 [True,True] -- should count as 2 - - --- Infeasible extension of a query with a data-polymorphic list case -extListQ'' :: Data d - => (d -> q) - -> (forall d. Data d => [d] -> q) - -> d -> q -extListQ'' def ext d = - if isList d - then undefined -- hard to avoid an ambiguous type - else def d - - --- Test extListQ from Data.Generics.Aliases -foo2 :: Data a => a -> Int -foo2 = const 0 `ext1Q` list - where - list :: Data a => [a] -> Int - list l = foldr (+) 0 $ map glength l - -t3 = foo2 (True,True) -- should count as 0 -t4 = foo2 [(True,True),(True,True)] -- should count as 2+2=4 - - --- Customisation for lists without type cast -foo3 :: Data a => a -> Int -foo3 x = if isList x - then foldr (+) 0 $ gmapListQ glength x - else 0 - -t5 = foo3 (True,True) -- should count as 0 -t6 = foo3 [(True,True),(True,True)] -- should count as 2+2=4 - - --- Test for list datatype -isList :: Data a => a -> Bool -isList x = typeRepTyCon (typeOf x) == - typeRepTyCon (typeOf (undefined::[()])) - - --- Test for nil -isNil :: Data a => a -> Bool -isNil x = toConstr x == toConstr ([]::[()]) - - --- Test for cons -isCons :: Data a => a -> Bool -isCons x = toConstr x == toConstr (():[]) - - --- gmapQ for polymorphic lists -gmapListQ :: forall a q. Data a => (forall a. Data a => a -> q) -> a -> [q] -gmapListQ f x = - if not $ isList x - then error "gmapListQ" - else if isNil x - then [] - else if isCons x - then ( gmapQi 0 f x : gmapQi 1 (gmapListQ f) x ) - else error "gmapListQ" - - --- Build nil -mkNil :: Data a => a -mkNil = fromConstr $ toConstr ([]::[()]) - - --- Build cons -mkCons :: Data a => a -mkCons = fromConstr $ toConstr ((undefined:undefined)::[()]) - - --- Main function for testing -tests = ( t1 - , ( t2 - , ( t3 - , ( t4 - , ( t5 - , ( t6 - )))))) ~=? output - -output = (0,(2,(0,(4,(0,4))))) +{-# OPTIONS -fglasgow-exts #-}+{-# LANGUAGE CPP #-}++module Ext1 (tests) where++{-++This example records some experiments with polymorphic datatypes.++-}++import Test.HUnit++import Data.Generics+#if MIN_VERSION_base(4,8,0)+import GHC.Base hiding(foldr)+#else+import GHC.Base+#endif++-- Unsafe coerce+unsafeCoerce :: a -> b+unsafeCoerce = unsafeCoerce#+++-- Handy type constructors+newtype ID x = ID { unID :: x }+newtype CONST c a = CONST { unCONST :: c }+++-- Extension of a query with a para. poly. list case+extListQ' :: Data d+ => (d -> q)+ -> (forall d. [d] -> q)+ -> d -> q+extListQ' def ext d =+ if isList d+ then ext (unsafeCoerce d)+ else def d +++-- Test extListQ'+foo1 :: Data d => d -> Int+foo1 = const 0 `extListQ'` length+t1 = foo1 True -- should count as 0+t2 = foo1 [True,True] -- should count as 2+++-- Infeasible extension of a query with a data-polymorphic list case+extListQ'' :: Data d+ => (d -> q)+ -> (forall d. Data d => [d] -> q)+ -> d -> q+extListQ'' def ext d =+ if isList d+ then undefined -- hard to avoid an ambiguous type+ else def d +++-- Test extListQ from Data.Generics.Aliases+foo2 :: Data a => a -> Int+foo2 = const 0 `ext1Q` list+ where+ list :: Data a => [a] -> Int+ list l = foldr (+) 0 $ map glength l++t3 = foo2 (True,True) -- should count as 0+t4 = foo2 [(True,True),(True,True)] -- should count as 2+2=4+++-- Customisation for lists without type cast+foo3 :: Data a => a -> Int+foo3 x = if isList x+ then foldr (+) 0 $ gmapListQ glength x+ else 0++t5 = foo3 (True,True) -- should count as 0+t6 = foo3 [(True,True),(True,True)] -- should count as 2+2=4+++-- Test for list datatype+isList :: Data a => a -> Bool+isList x = typeRepTyCon (typeOf x) ==+ typeRepTyCon (typeOf (undefined::[()]))+++-- Test for nil+isNil :: Data a => a -> Bool+isNil x = toConstr x == toConstr ([]::[()])+++-- Test for cons+isCons :: Data a => a -> Bool+isCons x = toConstr x == toConstr (():[])+++-- gmapQ for polymorphic lists+gmapListQ :: forall a q. Data a => (forall a. Data a => a -> q) -> a -> [q]+gmapListQ f x =+ if not $ isList x + then error "gmapListQ"+ else if isNil x+ then []+ else if isCons x+ then ( gmapQi 0 f x : gmapQi 1 (gmapListQ f) x )+ else error "gmapListQ"+++-- Build nil+mkNil :: Data a => a+mkNil = fromConstr $ toConstr ([]::[()])+++-- Build cons+mkCons :: Data a => a+mkCons = fromConstr $ toConstr ((undefined:undefined)::[()])+++-- Main function for testing+tests = ( t1+ , ( t2+ , ( t3+ , ( t4+ , ( t5+ , ( t6+ )))))) ~=? output++output = (0,(2,(0,(4,(0,4)))))
tests/Ext2.hs view
@@ -1,65 +1,65 @@-{-# LANGUAGE DeriveDataTypeable #-} - -module Ext2 (tests) where - --- Tests for ext2 and friends - -import Test.HUnit -import Data.Generics - - --- A type of lists -data List a = Nil | Cons a (List a) deriving (Data, Typeable, Show, Eq) - --- Example lists -l1, l2 :: List Int -l1 = Cons 1 (Cons 2 Nil) -l2 = Cons 0 l1 - --- A type of pairs -data Pair a b = Pair1 a b | Pair2 a b deriving (Data, Typeable, Show, Eq) - --- Example pairs -p1, p2 :: Pair Int Char -p1 = Pair1 2 'p' -p2 = Pair2 3 'q' - --- Structures containing the above -s1 :: [Pair Int Char] -s1 = [p1, p2] - -s2 :: (Pair Int Char, List Int) -s2 = (p2, l2) - - --- Auxiliary functions -unifyPair :: Pair a b -> Pair a b -> Bool -unifyPair (Pair1 _ _) (Pair1 _ _) = True -unifyPair (Pair2 _ _) (Pair2 _ _) = True -unifyPair _ _ = False - -flipPair :: Pair a b -> Pair a b -flipPair (Pair1 a b) = Pair2 a b -flipPair (Pair2 a b) = Pair1 a b - --- Tests -t1 = everywhere (id `ext2T` flipPair) (s1,s2) -t2 = let f :: (Data a) => a -> Maybe a - f = (const Nothing) `ext2M` (Just . flipPair) - in (f p1, f l1) -t3 = everything (+) ( const 0 - `ext1Q` (const 1 :: List a -> Int) - `ext2Q` (const 10 :: Pair a b -> Int)) - $ s2 -t4 = unifyPair (t4' :: Pair Int Char) t4' where - t4' :: Data a => a - t4' = undefined `ext1B` Nil `ext2B` (Pair1 undefined undefined) - - --- Main function for testing -tests = (t1, t2, t3, t4) ~=? output - -output = ((map flipPair s1, (flipPair p2, l2)) - ,(Just (flipPair p1),Nothing) - ,14 - ,True) +{-# LANGUAGE DeriveDataTypeable #-}++module Ext2 (tests) where++-- Tests for ext2 and friends++import Test.HUnit+import Data.Generics+++-- A type of lists+data List a = Nil | Cons a (List a) deriving (Data, Typeable, Show, Eq)++-- Example lists+l1, l2 :: List Int+l1 = Cons 1 (Cons 2 Nil)+l2 = Cons 0 l1++-- A type of pairs+data Pair a b = Pair1 a b | Pair2 a b deriving (Data, Typeable, Show, Eq)++-- Example pairs+p1, p2 :: Pair Int Char+p1 = Pair1 2 'p'+p2 = Pair2 3 'q'++-- Structures containing the above+s1 :: [Pair Int Char]+s1 = [p1, p2]++s2 :: (Pair Int Char, List Int)+s2 = (p2, l2)+++-- Auxiliary functions+unifyPair :: Pair a b -> Pair a b -> Bool+unifyPair (Pair1 _ _) (Pair1 _ _) = True+unifyPair (Pair2 _ _) (Pair2 _ _) = True+unifyPair _ _ = False++flipPair :: Pair a b -> Pair a b+flipPair (Pair1 a b) = Pair2 a b+flipPair (Pair2 a b) = Pair1 a b++-- Tests+t1 = everywhere (id `ext2T` flipPair) (s1,s2)+t2 = let f :: (Data a) => a -> Maybe a+ f = (const Nothing) `ext2M` (Just . flipPair)+ in (f p1, f l1)+t3 = everything (+) ( const 0+ `ext1Q` (const 1 :: List a -> Int)+ `ext2Q` (const 10 :: Pair a b -> Int))+ $ s2+t4 = unifyPair (t4' :: Pair Int Char) t4' where+ t4' :: Data a => a+ t4' = undefined `ext1B` Nil `ext2B` (Pair1 undefined undefined)+++-- Main function for testing+tests = (t1, t2, t3, t4) ~=? output++output = ((map flipPair s1, (flipPair p2, l2))+ ,(Just (flipPair p1),Nothing)+ ,14+ ,True)
tests/FoldTree.hs view
@@ -1,73 +1,73 @@-{-# LANGUAGE DeriveDataTypeable #-} -{-# LANGUAGE ScopedTypeVariables #-} - -{- - -A very, very simple example: "extract all Ints from a tree of Ints". -The text book approach is to write a generalised fold for that. One -can also turn the Tree datatype into functorial style and then write a -Functor instance for the functorial datatype including a definition of -fmap. (The original Tree datatype can be related to the functorial -version by the usual injection and projection.) - -You can scrap all such boilerplate by using a traversal scheme based -on gmap combinators as illustrated below. To get it a little more -interesting, we use a datatype Tree with not just a case for leafs and -fork trees, but we also add a case for trees with a weight. - -For completeness' sake, we mention that the fmap/generalised fold -approach differs from the gmap approach in some details. Most notably, -the gmap approach does not generally facilitate the identification of -term components that relate to the type parameter of a parameterised -datatype. The consequence of this is illustrated below as well. -Sec. 6.3 in "Scrap Your Boilerplate ..." discusses such `type -distinctions' as well. - --} - -module FoldTree (tests) where - -import Test.HUnit - --- Enable "ScrapYourBoilerplate" -import Data.Generics - - --- A parameterised datatype for binary trees with data at the leafs -data Tree a w = Leaf a - | Fork (Tree a w) (Tree a w) - | WithWeight (Tree a w) w - deriving (Typeable, Data) - - --- A typical tree -mytree :: Tree Int Int -mytree = Fork (WithWeight (Leaf 42) 1) - (WithWeight (Fork (Leaf 88) (Leaf 37)) 2) - --- A less typical tree, used for testing everythingBut -mytree' :: Tree Int Int -mytree' = Fork (Leaf 42) - (WithWeight (Fork (Leaf 88) (Leaf 37)) 2) - - --- Print everything like an Int in mytree --- In fact, we show two attempts: --- 1. print really just everything like an Int --- 2. print everything wrapped with Leaf --- So (1.) confuses leafs and weights whereas (2.) does not. --- Additionally we test everythingBut, stopping when we see a WithWeight node -tests = show ( listify (\(_::Int) -> True) mytree - , everything (++) ([] `mkQ` fromLeaf) mytree - , everythingBut (++) - (([],False) `mkQ` (\x -> (fromLeaf x, stop x))) mytree' - ) ~=? output - where - fromLeaf :: Tree Int Int -> [Int] - fromLeaf (Leaf x) = [x] - fromLeaf _ = [] - stop :: (Data a, Data b) => Tree a b -> Bool - stop (WithWeight _ _) = True - stop _ = False - -output = "([42,1,88,37,2],[42,88,37],[42])" +{-# LANGUAGE DeriveDataTypeable #-}+{-# LANGUAGE ScopedTypeVariables #-}++{-++A very, very simple example: "extract all Ints from a tree of Ints".+The text book approach is to write a generalised fold for that. One+can also turn the Tree datatype into functorial style and then write a+Functor instance for the functorial datatype including a definition of+fmap. (The original Tree datatype can be related to the functorial+version by the usual injection and projection.)++You can scrap all such boilerplate by using a traversal scheme based+on gmap combinators as illustrated below. To get it a little more+interesting, we use a datatype Tree with not just a case for leafs and+fork trees, but we also add a case for trees with a weight.++For completeness' sake, we mention that the fmap/generalised fold+approach differs from the gmap approach in some details. Most notably,+the gmap approach does not generally facilitate the identification of+term components that relate to the type parameter of a parameterised+datatype. The consequence of this is illustrated below as well.+Sec. 6.3 in "Scrap Your Boilerplate ..." discusses such `type+distinctions' as well.++-}++module FoldTree (tests) where++import Test.HUnit++-- Enable "ScrapYourBoilerplate"+import Data.Generics+++-- A parameterised datatype for binary trees with data at the leafs+data Tree a w = Leaf a+ | Fork (Tree a w) (Tree a w)+ | WithWeight (Tree a w) w + deriving (Typeable, Data)+++-- A typical tree+mytree :: Tree Int Int+mytree = Fork (WithWeight (Leaf 42) 1)+ (WithWeight (Fork (Leaf 88) (Leaf 37)) 2)++-- A less typical tree, used for testing everythingBut+mytree' :: Tree Int Int+mytree' = Fork (Leaf 42)+ (WithWeight (Fork (Leaf 88) (Leaf 37)) 2)+++-- Print everything like an Int in mytree+-- In fact, we show two attempts:+-- 1. print really just everything like an Int+-- 2. print everything wrapped with Leaf+-- So (1.) confuses leafs and weights whereas (2.) does not.+-- Additionally we test everythingBut, stopping when we see a WithWeight node+tests = show ( listify (\(_::Int) -> True) mytree+ , everything (++) ([] `mkQ` fromLeaf) mytree+ , everythingBut (++) + (([],False) `mkQ` (\x -> (fromLeaf x, stop x))) mytree'+ ) ~=? output+ where+ fromLeaf :: Tree Int Int -> [Int]+ fromLeaf (Leaf x) = [x]+ fromLeaf _ = []+ stop :: (Data a, Data b) => Tree a b -> Bool+ stop (WithWeight _ _) = True+ stop _ = False++output = "([42,1,88,37,2],[42,88,37],[42])"
tests/FreeNames.hs view
@@ -1,118 +1,118 @@-{-# OPTIONS -fglasgow-exts #-} - -module FreeNames (tests) where - -{- - -This example illustrates the kind of traversals that naturally show up -in language processing. That is, the free names (say, variables) are -derived for a given program fragment. To this end, we need several -worker functions that extract declaring and referencing occurrences -from given program fragments; see "decsExpr", "decsEqua", -etc. below. Then, we need a traversal "freeNames" that traverses over -the program fragment in a bottom-up manner so that free names from -subterms do not escape to the top when corresponding declarations are -provided. The "freeNames" algorithm uses set operations "union" and -"//" to compute sets of free names from the declared and referenced -names of the root term and free names of the immediate subterms. - -Contributed by Ralf Laemmel, ralf@cwi.nl - --} - -import Test.HUnit - -import Data.Generics -import Data.List - -data System = S [Function] deriving (Typeable, Data) - -data Function = F Name [Equation] deriving (Typeable, Data) - -data Equation = E [Pattern] Expression System deriving (Typeable, Data) - -data Pattern = PVar Name - | PTerm Name [Pattern] deriving (Typeable, Data) - -data Expression = Var Name - | App Expression Expression - | Lambda Name Expression deriving (Typeable, Data) - -type Name = String - --- A little sample program - -sys1 = S [f1,f2] -f1 = F "f1" [e11] -f2 = F "f2" [e21,e22] -e11 = E [] (Var "id") (S []) -e21 = E [ PTerm "C" [ PVar "x" ] ] (Var "x") (S []) -e22 = E [] (Var "id") (S []) - - --- Names declared in an expression -decsExpr :: Expression -> [Name] -decsExpr (Lambda n _) = [n] -decsExpr _ = [] - --- Names declared in an equation -decsEqua :: Equation -> [Name] -decsEqua (E ps _ _) = everything union ([] `mkQ` pvar) ps - where - pvar (PVar n) = [n] - pvar _ = [] - --- Names declared in a system -decsSyst :: System -> [Name] -decsSyst (S l) = nub $ map (\(F n _) -> n) l - --- Names referenced in an expression -refsExpr :: Expression -> [Name] -refsExpr (Var n) = [n] - --- Names referenced in an equation -refsEqua :: Equation -> [Name] -refsEqua (E ps _ _) = everything union ([] `mkQ` pterm) ps - where - pterm (PTerm n _) = [n] - pterm _ = [] - --- Combine the above type-specific cases to obtain --- generic functions that find declared and referenced names --- -decsFun :: Data a => a -> [Name] -decsFun = const [] `extQ` decsExpr `extQ` decsEqua `extQ` decsSyst - -refsFun :: Data a => a -> [Name] -refsFun = const [] `extQ` refsExpr `extQ` refsEqua - - - -{- - -Free name analysis: Take the union of free names obtained from the -immediate subterms (via gmapQ) and the names being referred to at the -root of the present term, but subtract all the names that are declared -at the root. - --} - -freeNames :: Data a => a -> [Name] -freeNames x = ( (refsFun x) - `union` - (nub . concat . gmapQ freeNames) x - ) \\ decsFun x - -{- - -Print the free names for the sample program sys1; see module -FunDatatypes.hs. This should print the list ["id","C"] because the -"Prelude" function "id" is used in the sample program, and also the -term constructor "C" occurs in a pattern; we assume a language without -explicit datatype declarations ;-) - --} - -tests = freeNames sys1 ~=? output - -output = ["id","C"] +{-# OPTIONS -fglasgow-exts #-}++module FreeNames (tests) where++{-++This example illustrates the kind of traversals that naturally show up+in language processing. That is, the free names (say, variables) are+derived for a given program fragment. To this end, we need several+worker functions that extract declaring and referencing occurrences+from given program fragments; see "decsExpr", "decsEqua",+etc. below. Then, we need a traversal "freeNames" that traverses over+the program fragment in a bottom-up manner so that free names from+subterms do not escape to the top when corresponding declarations are+provided. The "freeNames" algorithm uses set operations "union" and+"//" to compute sets of free names from the declared and referenced+names of the root term and free names of the immediate subterms.++Contributed by Ralf Laemmel, ralf@cwi.nl++-}++import Test.HUnit++import Data.Generics+import Data.List++data System = S [Function] deriving (Typeable, Data)++data Function = F Name [Equation] deriving (Typeable, Data)++data Equation = E [Pattern] Expression System deriving (Typeable, Data)++data Pattern = PVar Name+ | PTerm Name [Pattern] deriving (Typeable, Data)++data Expression = Var Name+ | App Expression Expression+ | Lambda Name Expression deriving (Typeable, Data)++type Name = String++-- A little sample program++sys1 = S [f1,f2]+f1 = F "f1" [e11]+f2 = F "f2" [e21,e22]+e11 = E [] (Var "id") (S [])+e21 = E [ PTerm "C" [ PVar "x" ] ] (Var "x") (S [])+e22 = E [] (Var "id") (S [])+++-- Names declared in an expression+decsExpr :: Expression -> [Name]+decsExpr (Lambda n _) = [n]+decsExpr _ = []++-- Names declared in an equation+decsEqua :: Equation -> [Name]+decsEqua (E ps _ _) = everything union ([] `mkQ` pvar) ps+ where+ pvar (PVar n) = [n]+ pvar _ = []++-- Names declared in a system+decsSyst :: System -> [Name]+decsSyst (S l) = nub $ map (\(F n _) -> n) l++-- Names referenced in an expression+refsExpr :: Expression -> [Name]+refsExpr (Var n) = [n]++-- Names referenced in an equation+refsEqua :: Equation -> [Name]+refsEqua (E ps _ _) = everything union ([] `mkQ` pterm) ps+ where+ pterm (PTerm n _) = [n]+ pterm _ = []++-- Combine the above type-specific cases to obtain+-- generic functions that find declared and referenced names+--+decsFun :: Data a => a -> [Name]+decsFun = const [] `extQ` decsExpr `extQ` decsEqua `extQ` decsSyst++refsFun :: Data a => a -> [Name]+refsFun = const [] `extQ` refsExpr `extQ` refsEqua++++{-++Free name analysis: Take the union of free names obtained from the+immediate subterms (via gmapQ) and the names being referred to at the+root of the present term, but subtract all the names that are declared+at the root.++-}+ +freeNames :: Data a => a -> [Name]+freeNames x = ( (refsFun x)+ `union`+ (nub . concat . gmapQ freeNames) x+ ) \\ decsFun x++{-++Print the free names for the sample program sys1; see module+FunDatatypes.hs. This should print the list ["id","C"] because the+"Prelude" function "id" is used in the sample program, and also the+term constructor "C" occurs in a pattern; we assume a language without+explicit datatype declarations ;-)++-}++tests = freeNames sys1 ~=? output++output = ["id","C"]
tests/GEq.hs view
@@ -1,21 +1,21 @@-{-# OPTIONS -fglasgow-exts #-} - -module GEq (tests) where - -{- - -This test exercices GENERIC read, show, and eq for the company -datatypes which we use a lot. The output of the program should be -"True" which means that "gread" reads what "gshow" shows while the -read term is equal to the original term in terms of "geq". - --} - -import Test.HUnit - -import Data.Generics -import CompanyDatatypes - -tests = ( geq genCom genCom - , geq genCom genCom' - ) ~=? (True,False) +{-# OPTIONS -fglasgow-exts #-}++module GEq (tests) where++{-++This test exercices GENERIC read, show, and eq for the company+datatypes which we use a lot. The output of the program should be+"True" which means that "gread" reads what "gshow" shows while the+read term is equal to the original term in terms of "geq".++-}++import Test.HUnit++import Data.Generics+import CompanyDatatypes++tests = ( geq genCom genCom+ , geq genCom genCom'+ ) ~=? (True,False)
tests/GMapQAssoc.hs view
@@ -1,68 +1,68 @@-{-# OPTIONS -fglasgow-exts #-} - -module GMapQAssoc (tests) where - -{- - -This example demonstrates the inadequacy of an apparently simpler -variation on gmapQ. To this end, let us first recall a few facts. -Firstly, function application (including constructor application) is -left-associative. This is the reason why we had preferred our generic -fold to be left-associative too. (In "The Sketch Of a Polymorphic -Symphony" you can find a right-associative generic fold.) Secondly, -lists are right-associative. Because of these inverse associativities -queries for the synthesis of lists require some extra effort to -reflect the left-to-right of immediate subterms in the queried list. -In the module Data.Generics, we solve the problem by a common -higher-order trick, that is, we do not cons lists during folding but -we pass functions on lists starting from the identity function and -passing [] to the resulting function. The following example -illustrates that we get indeed an undesirable right-to-left order if -we just apply the simple constant datatype constructor CONST instead -of the higher-order trick. - -Contributed by Ralf Laemmel, ralf@cwi.nl - --} - -import Test.HUnit - -import Data.Generics - - --- The plain constant type constructor -newtype CONST x y = CONST x -unCONST (CONST x) = x - - --- A variation on the gmapQ combinator using CONST and not Q -gmapQ' :: Data a => (forall a. Data a => a -> u) -> a -> [u] -gmapQ' f = unCONST . gfoldl f' z - where - f' r a = CONST (f a : unCONST r) - z = const (CONST []) - - --- A trivial datatype used for this test case -data IntTree = Leaf Int | Fork IntTree IntTree - deriving (Typeable, Data) - - --- Select int if faced with a leaf -leaf (Leaf i) = [i] -leaf _ = [] - - --- A test term -term = Fork (Leaf 1) (Leaf 2) - - --- Process test term --- gmapQ gives left-to-right order --- gmapQ' gives right-to-left order --- -tests = show ( gmapQ ([] `mkQ` leaf) term - , gmapQ' ([] `mkQ` leaf) term - ) ~=? output - -output = show ([[1],[2]],[[2],[1]]) +{-# OPTIONS -fglasgow-exts #-}++module GMapQAssoc (tests) where++{-++This example demonstrates the inadequacy of an apparently simpler+variation on gmapQ. To this end, let us first recall a few facts.+Firstly, function application (including constructor application) is+left-associative. This is the reason why we had preferred our generic+fold to be left-associative too. (In "The Sketch Of a Polymorphic+Symphony" you can find a right-associative generic fold.) Secondly,+lists are right-associative. Because of these inverse associativities+queries for the synthesis of lists require some extra effort to+reflect the left-to-right of immediate subterms in the queried list.+In the module Data.Generics, we solve the problem by a common+higher-order trick, that is, we do not cons lists during folding but+we pass functions on lists starting from the identity function and+passing [] to the resulting function. The following example+illustrates that we get indeed an undesirable right-to-left order if+we just apply the simple constant datatype constructor CONST instead+of the higher-order trick.++Contributed by Ralf Laemmel, ralf@cwi.nl++-}++import Test.HUnit++import Data.Generics+++-- The plain constant type constructor+newtype CONST x y = CONST x+unCONST (CONST x) = x+++-- A variation on the gmapQ combinator using CONST and not Q+gmapQ' :: Data a => (forall a. Data a => a -> u) -> a -> [u]+gmapQ' f = unCONST . gfoldl f' z+ where+ f' r a = CONST (f a : unCONST r)+ z = const (CONST [])+++-- A trivial datatype used for this test case+data IntTree = Leaf Int | Fork IntTree IntTree+ deriving (Typeable, Data)+++-- Select int if faced with a leaf +leaf (Leaf i) = [i]+leaf _ = []+++-- A test term+term = Fork (Leaf 1) (Leaf 2)+++-- Process test term+-- gmapQ gives left-to-right order+-- gmapQ' gives right-to-left order+--+tests = show ( gmapQ ([] `mkQ` leaf) term+ , gmapQ' ([] `mkQ` leaf) term+ ) ~=? output++output = show ([[1],[2]],[[2],[1]])
tests/GRead.hs view
@@ -1,45 +1,45 @@-{-# OPTIONS -fglasgow-exts #-} - -module GRead (tests) where - -{- - -The following examples achieve branch coverage for the various -productions in the definition of gread. Also, negative test cases are -provided; see str2 and str3. Also, the potential of heading or -trailing spaces as well incomplete parsing of the input is exercised; -see str5. - --} - -import Test.HUnit - -import Data.Generics - -str1 = "(True)" -- reads fine as a Bool -str2 = "(Treu)" -- invalid constructor -str3 = "True" -- lacks parentheses -str4 = "(1)" -- could be an Int -str5 = "( 2 ) ..." -- could be an Int with some trailing left-over -str6 = "([])" -- test empty list -str7 = "((:)" ++ " " ++ str4 ++ " " ++ str6 ++ ")" - -tests = show ( ( [ gread str1, - gread str2, - gread str3 - ] - , [ gread str4, - gread str5 - ] - , [ gread str6, - gread str7 - ] - ) - :: ( [[(Bool, String)]] - , [[(Int, String)]] - , [[([Int], String)]] - ) - ) ~=? output - -output = show - ([[(True,"")],[],[]],[[(1,"")],[(2,"...")]],[[([],"")],[([1],"")]]) +{-# OPTIONS -fglasgow-exts #-}++module GRead (tests) where++{-++The following examples achieve branch coverage for the various+productions in the definition of gread. Also, negative test cases are+provided; see str2 and str3. Also, the potential of heading or+trailing spaces as well incomplete parsing of the input is exercised;+see str5.++-}++import Test.HUnit++import Data.Generics++str1 = "(True)" -- reads fine as a Bool+str2 = "(Treu)" -- invalid constructor+str3 = "True" -- lacks parentheses+str4 = "(1)" -- could be an Int+str5 = "( 2 ) ..." -- could be an Int with some trailing left-over+str6 = "([])" -- test empty list+str7 = "((:)" ++ " " ++ str4 ++ " " ++ str6 ++ ")"++tests = show ( ( [ gread str1,+ gread str2,+ gread str3+ ]+ , [ gread str4,+ gread str5+ ]+ , [ gread str6,+ gread str7+ ]+ )+ :: ( [[(Bool, String)]]+ , [[(Int, String)]]+ , [[([Int], String)]]+ )+ ) ~=? output++output = show+ ([[(True,"")],[],[]],[[(1,"")],[(2,"...")]],[[([],"")],[([1],"")]])
tests/GRead2.hs view
@@ -1,75 +1,75 @@-{-# OPTIONS -fglasgow-exts #-} - -module GRead2 () where - -{- - -For the discussion in the 2nd boilerplate paper, -we favour some simplified generic read, which is checked to compile. -For the full/real story see Data.Generics.Text. - --} - -import Control.Applicative (Applicative(..)) -import Control.Monad (ap, liftM) -import Data.Generics - -gread :: Data a => String -> Maybe a -gread input = runDec input readM - --- The decoder monad -newtype DecM a = D (String -> Maybe (String, a)) - -instance Functor DecM where - fmap = liftM - -instance Applicative DecM where - pure = return - (<*>) = ap - -instance Monad DecM where - return a = D (\s -> Just (s,a)) - (D m) >>= k = D (\s -> - case m s of - Nothing -> Nothing - Just (s1,a) -> let D n = k a - in n s1) - -runDec :: String -> DecM a -> Maybe a -runDec input (D m) = do (_,x) <- m input - return x - -parseConstr :: DataType -> DecM Constr -parseConstr ty = D (\s -> - match s (dataTypeConstrs ty)) - where - match :: String -> [Constr] - -> Maybe (String, Constr) - match _ [] = Nothing - match input (con:cons) - | take n input == showConstr con - = Just (drop n input, con) - | otherwise - = match input cons - where - n = length (showConstr con) - - -readM :: forall a. Data a => DecM a -readM = read - where - read :: DecM a - read = do { let val = argOf read - ; let ty = dataTypeOf val - ; constr <- parseConstr ty - ; let con::a = fromConstr constr - ; gmapM (\_ -> readM) con } - -argOf :: c a -> a -argOf = undefined - -yareadM :: forall a. Data a => DecM a -yareadM = do { let ty = dataTypeOf (undefined::a) - ; constr <- parseConstr ty - ; let con::a = fromConstr constr - ; gmapM (\_ -> yareadM) con } +{-# OPTIONS -fglasgow-exts #-}++module GRead2 () where++{-++For the discussion in the 2nd boilerplate paper,+we favour some simplified generic read, which is checked to compile.+For the full/real story see Data.Generics.Text.++-}++import Control.Applicative (Applicative(..))+import Control.Monad (ap, liftM)+import Data.Generics++gread :: Data a => String -> Maybe a+gread input = runDec input readM++-- The decoder monad+newtype DecM a = D (String -> Maybe (String, a))++instance Functor DecM where+ fmap = liftM++instance Applicative DecM where+ pure = return+ (<*>) = ap++instance Monad DecM where+ return a = D (\s -> Just (s,a))+ (D m) >>= k = D (\s ->+ case m s of+ Nothing -> Nothing+ Just (s1,a) -> let D n = k a+ in n s1)+ +runDec :: String -> DecM a -> Maybe a+runDec input (D m) = do (_,x) <- m input+ return x++parseConstr :: DataType -> DecM Constr+parseConstr ty = D (\s ->+ match s (dataTypeConstrs ty))+ where+ match :: String -> [Constr]+ -> Maybe (String, Constr)+ match _ [] = Nothing+ match input (con:cons)+ | take n input == showConstr con+ = Just (drop n input, con)+ | otherwise+ = match input cons+ where+ n = length (showConstr con)+++readM :: forall a. Data a => DecM a+readM = read+ where+ read :: DecM a+ read = do { let val = argOf read+ ; let ty = dataTypeOf val+ ; constr <- parseConstr ty+ ; let con::a = fromConstr constr+ ; gmapM (\_ -> readM) con }++argOf :: c a -> a+argOf = undefined++yareadM :: forall a. Data a => DecM a+yareadM = do { let ty = dataTypeOf (undefined::a)+ ; constr <- parseConstr ty+ ; let con::a = fromConstr constr+ ; gmapM (\_ -> yareadM) con }
tests/GShow.hs view
@@ -1,52 +1,52 @@-{-# OPTIONS -fglasgow-exts #-} - -module GShow (tests) where - -{- - -The generic show example from the 2nd boilerplate paper. -(There were some typos in the ICFP 2004 paper.) -Also check out Data.Generics.Text. - --} - -import Test.HUnit - -import Data.Generics hiding (gshow) -import Prelude hiding (showString) - - -gshow :: Data a => a -> String -gshow = gshow_help `extQ` showString - -gshow_help :: Data a => a -> String -gshow_help t - = "(" - ++ showConstr (toConstr t) - ++ concat (intersperse " " (gmapQ gshow t)) - ++ ")" - -showString :: String -> String -showString s = "\"" ++ concat (map escape s) ++ "\"" - where - escape '\n' = "\\n" - escape other_char = [other_char] - -gshowList :: Data b => [b] -> String -gshowList xs - = "[" ++ concat (intersperse "," (map gshow xs)) ++ "]" - -gshow' :: Data a => a -> String -gshow' = gshow_help `ext1Q` gshowList - `extQ` showString - -intersperse :: a -> [a] -> [a] -intersperse _ [] = [] -intersperse x [e] = [e] -intersperse x (e:es) = (e:(x:intersperse x es)) - -tests = ( gshow' "foo" - , gshow' [True,False] - ) ~=? output - -output = ("\"foo\"","[(True),(False)]") +{-# OPTIONS -fglasgow-exts #-}+ +module GShow (tests) where++{-+ +The generic show example from the 2nd boilerplate paper.+(There were some typos in the ICFP 2004 paper.)+Also check out Data.Generics.Text.+ +-}++import Test.HUnit++import Data.Generics hiding (gshow)+import Prelude hiding (showString)++ +gshow :: Data a => a -> String+gshow = gshow_help `extQ` showString++gshow_help :: Data a => a -> String+gshow_help t + = "("+ ++ showConstr (toConstr t)+ ++ concat (intersperse " " (gmapQ gshow t))+ ++ ")"++showString :: String -> String+showString s = "\"" ++ concat (map escape s) ++ "\"" + where+ escape '\n' = "\\n"+ escape other_char = [other_char]++gshowList :: Data b => [b] -> String+gshowList xs+ = "[" ++ concat (intersperse "," (map gshow xs)) ++ "]"++gshow' :: Data a => a -> String+gshow' = gshow_help `ext1Q` gshowList + `extQ` showString++intersperse :: a -> [a] -> [a]+intersperse _ [] = []+intersperse x [e] = [e]+intersperse x (e:es) = (e:(x:intersperse x es))++tests = ( gshow' "foo"+ , gshow' [True,False]+ ) ~=? output++output = ("\"foo\"","[(True),(False)]")
tests/GShow2.hs view
@@ -1,47 +1,47 @@-{-# OPTIONS -fglasgow-exts #-} - -module GShow2 (tests) where - -{- - -This test exercices GENERIC show for the infamous company datatypes. The -output of the program should be some representation of the infamous -"genCom" company. - --} - -import Test.HUnit - -import Data.Generics -import CompanyDatatypes - -tests = gshow genCom ~=? output - -{- - -Here is another exercise: -The following function gshow' is a completely generic variation on gshow. -It would print strings as follows: - -*Main> gshow' "abc" -"((:) ('a') ((:) ('b') ((:) ('c') ([]))))" - -The original gshow does a better job because it is customised for strings: - -*Main> gshow "foo" -"\"foo\"" - -In fact, this is what Haskell's normal show would also do: - -*Main> show "foo" -"\"foo\"" - --} - -gshow' :: Data a => a -> String -gshow' t = "(" - ++ showConstr (toConstr t) - ++ concat (gmapQ ((++) " " . gshow') t) - ++ ")" - -output = "(C ((:) (D \"Research\" (E (P \"Laemmel\" \"Amsterdam\") (S (8000.0))) ((:) (PU (E (P \"Joost\" \"Amsterdam\") (S (1000.0)))) ((:) (PU (E (P \"Marlow\" \"Cambridge\") (S (2000.0)))) ([])))) ((:) (D \"Strategy\" (E (P \"Blair\" \"London\") (S (100000.0))) ([])) ([]))))" +{-# OPTIONS -fglasgow-exts #-}++module GShow2 (tests) where++{-++This test exercices GENERIC show for the infamous company datatypes. The+output of the program should be some representation of the infamous+"genCom" company.++-}++import Test.HUnit++import Data.Generics+import CompanyDatatypes++tests = gshow genCom ~=? output++{-++Here is another exercise:+The following function gshow' is a completely generic variation on gshow.+It would print strings as follows:++*Main> gshow' "abc"+"((:) ('a') ((:) ('b') ((:) ('c') ([]))))"++The original gshow does a better job because it is customised for strings:++*Main> gshow "foo"+"\"foo\""++In fact, this is what Haskell's normal show would also do:++*Main> show "foo"+"\"foo\""++-}++gshow' :: Data a => a -> String+gshow' t = "("+ ++ showConstr (toConstr t)+ ++ concat (gmapQ ((++) " " . gshow') t)+ ++ ")"++output = "(C ((:) (D \"Research\" (E (P \"Laemmel\" \"Amsterdam\") (S (8000.0))) ((:) (PU (E (P \"Joost\" \"Amsterdam\") (S (1000.0)))) ((:) (PU (E (P \"Marlow\" \"Cambridge\") (S (2000.0)))) ([])))) ((:) (D \"Strategy\" (E (P \"Blair\" \"London\") (S (100000.0))) ([])) ([]))))"
tests/GZip.hs view
@@ -1,46 +1,46 @@-{-# OPTIONS -fglasgow-exts #-} - -module GZip (tests) where - -{- - -This test illustrates zipping for the company datatypes which we use a -lot. We process two companies that happen to agree on the overall -shape but differ in the salaries in a few positions. So whenever we -encounter salaries we take the maximum of the two. - --} - -import Test.HUnit - -import Data.Generics -import CompanyDatatypes - --- The main function which prints the result of zipping -tests = gzip (\x y -> mkTT maxS x y) genCom1 genCom2 ~=? output - -- NB: the argument has to be eta-expanded to match - -- the type of gzip's argument type, which is - -- GenericQ (GenericM Maybe) - where - - -- Variations on the show case company "genCom" - genCom1 = everywhere (mkT (double "Joost")) genCom - genCom2 = everywhere (mkT (double "Marlow")) genCom - double x (E p@(P y _) (S s)) | x == y = E p (S (2*s)) - double _ e = e - - -- Sum up two salaries - maxS (S x) (S y) = S (max x y) - - -- Make a two-arguments, generic function transformer - mkTT :: (Typeable a, Typeable b, Typeable c) - => (a -> a -> a) -> b -> c -> Maybe c - mkTT (f::a -> a -> a) x y = - case (cast x,cast y) of - (Just (x'::a),Just (y'::a)) -> cast (f x' y') - _ -> Nothing - -output = Just (C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8000.0)) - [PU (E (P "Joost" "Amsterdam") (S 2000.0)) - ,PU (E (P "Marlow" "Cambridge") (S 4000.0))] - ,D "Strategy" (E (P "Blair" "London") (S 100000.0)) []]) +{-# OPTIONS -fglasgow-exts #-}++module GZip (tests) where++{-++This test illustrates zipping for the company datatypes which we use a+lot. We process two companies that happen to agree on the overall+shape but differ in the salaries in a few positions. So whenever we+encounter salaries we take the maximum of the two.++-}++import Test.HUnit++import Data.Generics+import CompanyDatatypes++-- The main function which prints the result of zipping+tests = gzip (\x y -> mkTT maxS x y) genCom1 genCom2 ~=? output+ -- NB: the argument has to be eta-expanded to match+ -- the type of gzip's argument type, which is+ -- GenericQ (GenericM Maybe)+ where++ -- Variations on the show case company "genCom"+ genCom1 = everywhere (mkT (double "Joost")) genCom+ genCom2 = everywhere (mkT (double "Marlow")) genCom+ double x (E p@(P y _) (S s)) | x == y = E p (S (2*s))+ double _ e = e++ -- Sum up two salaries+ maxS (S x) (S y) = S (max x y)++ -- Make a two-arguments, generic function transformer+ mkTT :: (Typeable a, Typeable b, Typeable c)+ => (a -> a -> a) -> b -> c -> Maybe c+ mkTT (f::a -> a -> a) x y =+ case (cast x,cast y) of+ (Just (x'::a),Just (y'::a)) -> cast (f x' y')+ _ -> Nothing++output = Just (C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8000.0)) + [PU (E (P "Joost" "Amsterdam") (S 2000.0))+ ,PU (E (P "Marlow" "Cambridge") (S 4000.0))]+ ,D "Strategy" (E (P "Blair" "London") (S 100000.0)) []])
tests/GenUpTo.hs view
@@ -1,94 +1,94 @@-{-# OPTIONS -fglasgow-exts #-} - -module GenUpTo (tests) where - -{- - -This example illustrate test-set generation, -namely all terms of a given depth are generated. - --} - -import Test.HUnit - -import Data.Generics - - -{- - -The following datatypes comprise the abstract syntax of a simple -imperative language. Some provisions are such that the discussion -of test-set generation is simplified. In particular, we do not -consider anything but monomorphic *data*types --- no primitive -types, no tuples, ... - --} - -data Prog = Prog Dec Stat - deriving (Show, Eq, Typeable, Data) - -data Dec = Nodec - | Ondec Id Type - | Manydecs Dec Dec - deriving (Show, Eq, Typeable, Data) - -data Id = A | B - deriving (Show, Eq, Typeable, Data) - -data Type = Int | Bool - deriving (Show, Eq, Typeable, Data) - -data Stat = Noop - | Assign Id Exp - | Seq Stat Stat - deriving (Show, Eq, Typeable, Data) - -data Exp = Zero - | Succ Exp - deriving (Show, Eq, Typeable, Data) - - --- Generate all terms of a given depth -genUpTo :: Data a => Int -> [a] -genUpTo 0 = [] -genUpTo d = result - where - -- Getting hold of the result (type) - result = concat (map recurse cons) - - -- Retrieve constructors of the requested type - cons :: [Constr] - cons = dataTypeConstrs (dataTypeOf (head result)) - - -- Find all terms headed by a specific Constr - recurse :: Data a => Constr -> [a] - recurse con = gmapM (\_ -> genUpTo (d-1)) - (fromConstr con) - - -- We could also deal with primitive types easily. - -- Then we had to use cons' instead of cons. - -- - cons' :: [Constr] - cons' = case dataTypeRep ty of - AlgRep cons -> cons - IntRep -> [mkIntegralConstr ty 0] - FloatRep -> [mkIntegralConstr ty 0] - CharRep -> [mkCharConstr ty 'x'] - where - ty = dataTypeOf (head result) - - --- For silly tests -data T0 = T0 T1 T2 T3 deriving (Show, Eq, Typeable, Data) -data T1 = T1a | T1b deriving (Show, Eq, Typeable, Data) -data T2 = T2a | T2b deriving (Show, Eq, Typeable, Data) -data T3 = T3a | T3b deriving (Show, Eq, Typeable, Data) - -tests = ( genUpTo 0 :: [Id] - , ( genUpTo 1 :: [Id] - , ( genUpTo 2 :: [Id] - , ( genUpTo 2 :: [T0] - , ( genUpTo 3 :: [Prog] - ))))) ~=? output - -output = ([],([A,B],([A,B],([T0 T1a T2a T3a,T0 T1a T2a T3b,T0 T1a T2b T3a,T0 T1a T2b T3b,T0 T1b T2a T3a,T0 T1b T2a T3b,T0 T1b T2b T3a,T0 T1b T2b T3b],[Prog Nodec Noop,Prog Nodec (Assign A Zero),Prog Nodec (Assign B Zero),Prog Nodec (Seq Noop Noop),Prog (Ondec A Int) Noop,Prog (Ondec A Int) (Assign A Zero),Prog (Ondec A Int) (Assign B Zero),Prog (Ondec A Int) (Seq Noop Noop),Prog (Ondec A Bool) Noop,Prog (Ondec A Bool) (Assign A Zero),Prog (Ondec A Bool) (Assign B Zero),Prog (Ondec A Bool) (Seq Noop Noop),Prog (Ondec B Int) Noop,Prog (Ondec B Int) (Assign A Zero),Prog (Ondec B Int) (Assign B Zero),Prog (Ondec B Int) (Seq Noop Noop),Prog (Ondec B Bool) Noop,Prog (Ondec B Bool) (Assign A Zero),Prog (Ondec B Bool) (Assign B Zero),Prog (Ondec B Bool) (Seq Noop Noop),Prog (Manydecs Nodec Nodec) Noop,Prog (Manydecs Nodec Nodec) (Assign A Zero),Prog (Manydecs Nodec Nodec) (Assign B Zero),Prog (Manydecs Nodec Nodec) (Seq Noop Noop)])))) +{-# OPTIONS -fglasgow-exts #-}++module GenUpTo (tests) where++{-++This example illustrate test-set generation,+namely all terms of a given depth are generated.++-}++import Test.HUnit++import Data.Generics+++{-++The following datatypes comprise the abstract syntax of a simple+imperative language. Some provisions are such that the discussion+of test-set generation is simplified. In particular, we do not +consider anything but monomorphic *data*types --- no primitive+types, no tuples, ...++-}+ +data Prog = Prog Dec Stat + deriving (Show, Eq, Typeable, Data)++data Dec = Nodec+ | Ondec Id Type + | Manydecs Dec Dec+ deriving (Show, Eq, Typeable, Data)++data Id = A | B+ deriving (Show, Eq, Typeable, Data)++data Type = Int | Bool+ deriving (Show, Eq, Typeable, Data)++data Stat = Noop+ | Assign Id Exp+ | Seq Stat Stat+ deriving (Show, Eq, Typeable, Data)++data Exp = Zero + | Succ Exp+ deriving (Show, Eq, Typeable, Data)+++-- Generate all terms of a given depth+genUpTo :: Data a => Int -> [a]+genUpTo 0 = []+genUpTo d = result+ where+ -- Getting hold of the result (type)+ result = concat (map recurse cons)++ -- Retrieve constructors of the requested type+ cons :: [Constr]+ cons = dataTypeConstrs (dataTypeOf (head result))++ -- Find all terms headed by a specific Constr+ recurse :: Data a => Constr -> [a]+ recurse con = gmapM (\_ -> genUpTo (d-1)) + (fromConstr con)++ -- We could also deal with primitive types easily.+ -- Then we had to use cons' instead of cons.+ --+ cons' :: [Constr]+ cons' = case dataTypeRep ty of+ AlgRep cons -> cons+ IntRep -> [mkIntegralConstr ty 0]+ FloatRep -> [mkIntegralConstr ty 0]+ CharRep -> [mkCharConstr ty 'x']+ where+ ty = dataTypeOf (head result) +++-- For silly tests+data T0 = T0 T1 T2 T3 deriving (Show, Eq, Typeable, Data)+data T1 = T1a | T1b deriving (Show, Eq, Typeable, Data)+data T2 = T2a | T2b deriving (Show, Eq, Typeable, Data)+data T3 = T3a | T3b deriving (Show, Eq, Typeable, Data)++tests = ( genUpTo 0 :: [Id]+ , ( genUpTo 1 :: [Id]+ , ( genUpTo 2 :: [Id]+ , ( genUpTo 2 :: [T0]+ , ( genUpTo 3 :: [Prog]+ ))))) ~=? output++output = ([],([A,B],([A,B],([T0 T1a T2a T3a,T0 T1a T2a T3b,T0 T1a T2b T3a,T0 T1a T2b T3b,T0 T1b T2a T3a,T0 T1b T2a T3b,T0 T1b T2b T3a,T0 T1b T2b T3b],[Prog Nodec Noop,Prog Nodec (Assign A Zero),Prog Nodec (Assign B Zero),Prog Nodec (Seq Noop Noop),Prog (Ondec A Int) Noop,Prog (Ondec A Int) (Assign A Zero),Prog (Ondec A Int) (Assign B Zero),Prog (Ondec A Int) (Seq Noop Noop),Prog (Ondec A Bool) Noop,Prog (Ondec A Bool) (Assign A Zero),Prog (Ondec A Bool) (Assign B Zero),Prog (Ondec A Bool) (Seq Noop Noop),Prog (Ondec B Int) Noop,Prog (Ondec B Int) (Assign A Zero),Prog (Ondec B Int) (Assign B Zero),Prog (Ondec B Int) (Seq Noop Noop),Prog (Ondec B Bool) Noop,Prog (Ondec B Bool) (Assign A Zero),Prog (Ondec B Bool) (Assign B Zero),Prog (Ondec B Bool) (Seq Noop Noop),Prog (Manydecs Nodec Nodec) Noop,Prog (Manydecs Nodec Nodec) (Assign A Zero),Prog (Manydecs Nodec Nodec) (Assign B Zero),Prog (Manydecs Nodec Nodec) (Seq Noop Noop)]))))
tests/GetC.hs view
@@ -1,121 +1,121 @@-{-# OPTIONS -fglasgow-exts #-} -{-# LANGUAGE OverlappingInstances, UndecidableInstances #-} - -module GetC (tests) where - -import Test.HUnit - -{- - -Ralf Laemmel, 5 November 2004 - -Joe Stoy suggested the idiom to test for the outermost constructor. - -Given is a term t -and a constructor f (say the empty constructor application). - -isC f t returns True if the outermost constructor of t is f. -isC f t returns False otherwise. -Modulo type checking, i.e., the data type of f and t must be the same. -If not, we want to see a type error, of course. - --} - -import Data.Typeable -- to cast t's subterms, which will be reused for f. -import Data.Generics -- to access t's subterms and constructors. - - --- Some silly data types -data T1 = T1a Int String | T1b String Int deriving (Typeable, Data) -data T2 = T2a Int Int | T2b String String deriving (Typeable, Data) -data T3 = T3! Int deriving (Typeable, Data) - - --- Test cases -tests = show [ isC T1a (T1a 1 "foo") -- typechecks, returns True - , isC T1a (T1b "foo" 1) -- typechecks, returns False - , isC T3 (T3 42)] -- works for strict data too - ~=? output --- err = show $ isC T2b (T1b "foo" 1) -- must not typecheck - -output = show [True,False,True] - --- --- We look at a datum a. --- We look at a constructor function f. --- The class GetT checks that f constructs data of type a. --- The class GetC computes maybe the constructor ... --- ... if the subterms of the datum at hand fit for f. --- Finally we compare the constructors. --- - -isC :: (Data a, GetT f a, GetC f) => f -> a -> Bool -isC f t = maybe False ((==) (toConstr t)) con - where - kids = gmapQ ExTypeable t -- homogenify subterms in list for reuse - con = getC f kids -- compute constructor from constructor application - - --- --- We prepare for a list of kids using existential envelopes. --- We could also just operate on TypeReps for non-strict datatypes. --- - -data ExTypeable = forall a. Typeable a => ExTypeable a -unExTypeable (ExTypeable a) = cast a - - --- --- Compute the result type of a function type. --- Beware: the TypeUnify constraint causes headache. --- We can't have GetT t t because the FD will be violated then. --- We can't omit the FD because unresolvable overlapping will hold then. --- - -class GetT f t | f -> t -- FD is optional -instance GetT g t => GetT (x -> g) t -instance TypeUnify t t' => GetT t t' - - --- --- Obtain the constructor if term can be completed --- - -class GetC f - where - getC :: f -> [ExTypeable] -> Maybe Constr - -instance (Typeable x, GetC g) => GetC (x -> g) - where - getC _ [] = Nothing - getC (f::x->g) (h:t) - = - do - (x::x) <- unExTypeable h - getC (f x) t - -instance Data t => GetC t - where - getC y [] = Just $ toConstr y - getC _ (_:_) = Nothing - - --- --- Type unification; we could try this: --- class TypeUnify a b | a -> b, b -> a --- instance TypeUnify a a --- --- However, if the instance is placed in the present module, --- then type improvement would inline this instance. Sigh!!! --- --- So we need type unification with type improvement blocker --- The following solution works with GHC for ages. --- Other solutions; see the HList paper. --- - -class TypeUnify a b | a -> b, b -> a -class TypeUnify' x a b | x a -> b, x b -> a -class TypeUnify'' x a b | x a -> b, x b -> a -instance TypeUnify' () a b => TypeUnify a b -instance TypeUnify'' x a b => TypeUnify' x a b -instance TypeUnify'' () a a +{-# OPTIONS -fglasgow-exts #-}+{-# LANGUAGE OverlappingInstances, UndecidableInstances #-}++module GetC (tests) where++import Test.HUnit++{-++Ralf Laemmel, 5 November 2004 ++Joe Stoy suggested the idiom to test for the outermost constructor.++Given is a term t+and a constructor f (say the empty constructor application).++isC f t returns True if the outermost constructor of t is f.+isC f t returns False otherwise.+Modulo type checking, i.e., the data type of f and t must be the same.+If not, we want to see a type error, of course.++-}++import Data.Typeable -- to cast t's subterms, which will be reused for f.+import Data.Generics -- to access t's subterms and constructors.+++-- Some silly data types+data T1 = T1a Int String | T1b String Int deriving (Typeable, Data)+data T2 = T2a Int Int | T2b String String deriving (Typeable, Data)+data T3 = T3! Int deriving (Typeable, Data)+++-- Test cases+tests = show [ isC T1a (T1a 1 "foo") -- typechecks, returns True+ , isC T1a (T1b "foo" 1) -- typechecks, returns False+ , isC T3 (T3 42)] -- works for strict data too+ ~=? output+-- err = show $ isC T2b (T1b "foo" 1) -- must not typecheck++output = show [True,False,True]++--+-- We look at a datum a.+-- We look at a constructor function f.+-- The class GetT checks that f constructs data of type a.+-- The class GetC computes maybe the constructor ...+-- ... if the subterms of the datum at hand fit for f.+-- Finally we compare the constructors.+-- ++isC :: (Data a, GetT f a, GetC f) => f -> a -> Bool+isC f t = maybe False ((==) (toConstr t)) con+ where+ kids = gmapQ ExTypeable t -- homogenify subterms in list for reuse+ con = getC f kids -- compute constructor from constructor application+++--+-- We prepare for a list of kids using existential envelopes.+-- We could also just operate on TypeReps for non-strict datatypes.+-- ++data ExTypeable = forall a. Typeable a => ExTypeable a+unExTypeable (ExTypeable a) = cast a+++-- +-- Compute the result type of a function type.+-- Beware: the TypeUnify constraint causes headache.+-- We can't have GetT t t because the FD will be violated then.+-- We can't omit the FD because unresolvable overlapping will hold then. +-- ++class GetT f t | f -> t -- FD is optional+instance GetT g t => GetT (x -> g) t+instance TypeUnify t t' => GetT t t'+++--+-- Obtain the constructor if term can be completed+-- ++class GetC f+ where+ getC :: f -> [ExTypeable] -> Maybe Constr++instance (Typeable x, GetC g) => GetC (x -> g)+ where+ getC _ [] = Nothing+ getC (f::x->g) (h:t)+ =+ do+ (x::x) <- unExTypeable h+ getC (f x) t++instance Data t => GetC t+ where+ getC y [] = Just $ toConstr y+ getC _ (_:_) = Nothing+++--+-- Type unification; we could try this:+-- class TypeUnify a b | a -> b, b -> a+-- instance TypeUnify a a+-- +-- However, if the instance is placed in the present module,+-- then type improvement would inline this instance. Sigh!!!+--+-- So we need type unification with type improvement blocker+-- The following solution works with GHC for ages.+-- Other solutions; see the HList paper.+--++class TypeUnify a b | a -> b, b -> a+class TypeUnify' x a b | x a -> b, x b -> a +class TypeUnify'' x a b | x a -> b, x b -> a +instance TypeUnify' () a b => TypeUnify a b+instance TypeUnify'' x a b => TypeUnify' x a b+instance TypeUnify'' () a a
tests/HList.hs view
@@ -1,62 +1,62 @@-{-# OPTIONS -fglasgow-exts #-} - -module HList (tests) where - -{- - -This module illustrates heterogeneously typed lists. - --} - -import Test.HUnit - -import Data.Typeable - - --- Heterogeneously typed lists -type HList = [DontKnow] - -data DontKnow = forall a. Typeable a => DontKnow a - --- The empty list -initHList :: HList -initHList = [] - --- Add an entry -addHList :: Typeable a => a -> HList -> HList -addHList a l = (DontKnow a:l) - --- Test for an empty list -nullHList :: HList -> Bool -nullHList = null - --- Retrieve head by type case -headHList :: Typeable a => HList -> Maybe a -headHList [] = Nothing -headHList (DontKnow a:_) = cast a - --- Retrieve tail by type case -tailHList :: HList -> HList -tailHList = tail - --- Access per index; starts at 1 -nth1HList :: Typeable a => Int -> HList -> Maybe a -nth1HList i l = case (l !! (i-1)) of (DontKnow a) -> cast a - - ----------------------------------------------------------------------------- - --- A demo list -mylist = addHList (1::Int) $ - addHList (True::Bool) $ - addHList ("42"::String) $ - initHList - --- Main function for testing -tests = ( show (nth1HList 1 mylist :: Maybe Int) -- shows Just 1 - , ( show (nth1HList 1 mylist :: Maybe Bool) -- shows Nothing - , ( show (nth1HList 2 mylist :: Maybe Bool) -- shows Just True - , ( show (nth1HList 3 mylist :: Maybe String) -- shows Just "42" - )))) ~=? output - +{-# OPTIONS -fglasgow-exts #-}++module HList (tests) where++{-++This module illustrates heterogeneously typed lists.++-}++import Test.HUnit++import Data.Typeable+++-- Heterogeneously typed lists+type HList = [DontKnow]++data DontKnow = forall a. Typeable a => DontKnow a ++-- The empty list+initHList :: HList+initHList = []++-- Add an entry+addHList :: Typeable a => a -> HList -> HList+addHList a l = (DontKnow a:l)++-- Test for an empty list+nullHList :: HList -> Bool+nullHList = null++-- Retrieve head by type case+headHList :: Typeable a => HList -> Maybe a+headHList [] = Nothing+headHList (DontKnow a:_) = cast a++-- Retrieve tail by type case+tailHList :: HList -> HList+tailHList = tail++-- Access per index; starts at 1+nth1HList :: Typeable a => Int -> HList -> Maybe a+nth1HList i l = case (l !! (i-1)) of (DontKnow a) -> cast a+++----------------------------------------------------------------------------++-- A demo list+mylist = addHList (1::Int) $+ addHList (True::Bool) $+ addHList ("42"::String) $+ initHList++-- Main function for testing+tests = ( show (nth1HList 1 mylist :: Maybe Int) -- shows Just 1+ , ( show (nth1HList 1 mylist :: Maybe Bool) -- shows Nothing+ , ( show (nth1HList 2 mylist :: Maybe Bool) -- shows Just True+ , ( show (nth1HList 3 mylist :: Maybe String) -- shows Just "42"+ )))) ~=? output+ output = ("Just 1",("Nothing",("Just True","Just \"42\"")))
tests/HOPat.hs view
@@ -1,67 +1,67 @@-{-# OPTIONS -fglasgow-exts #-} - -module HOPat (tests) where - -{- - -This module is in reply to an email by C. Barry Jay -received on March 15, and handled within hours. CBJ -raises the very interesting issue of higher-order patterns. -It turns out that some form of it is readily covered in -our setting. - --} - -import Test.HUnit - -import Data.Generics - - --- Sample datatypes -data T1 = T1a Int | T1b Float - deriving (Show, Eq, Typeable, Data) -data T2 = T2a T1 T2 | T2b - deriving (Show, Eq, Typeable, Data) - --- Eliminate a constructor if feasible -elim' :: (Data y, Data x) => Constr -> y -> Maybe x -elim' c y = if toConstr y == c - then unwrap y - else Nothing - - --- Unwrap a term; Return its single component -unwrap :: (Data y, Data x) => y -> Maybe x -unwrap y = case gmapQ (Nothing `mkQ` Just) y of - [Just x] -> Just x - _ -> Nothing - - --- Eliminate a constructor if feasible; 2nd try -elim :: forall x y. (Data y, Data x) => (x -> y) -> y -> Maybe x -elim c y = elim' (toConstr (c (undefined::x))) y - - --- Visit a data structure -visitor :: (Data x, Data y, Data z) - => (x -> y) -> (x -> x) -> z -> z -visitor c f = everywhere (mkT g) - where - g y = case elim c y of - Just x -> c (f x) - Nothing -> y - - --- Main function for testing -tests = ( ( elim' (toConstr t1a) t1a) :: Maybe Int - , ( (elim' (toConstr t1a) t1b) :: Maybe Int - , ( (elim T1a t1a) :: Maybe Int - , ( (elim T1a t1b) :: Maybe Int - , ( (visitor T1a ((+) 46) t2) :: T2 - ))))) ~=? output - where - t1a = T1a 42 - t1b = T1b 3.14 - t2 = T2a t1a (T2a t1a T2b) - +{-# OPTIONS -fglasgow-exts #-}++module HOPat (tests) where++{-++This module is in reply to an email by C. Barry Jay+received on March 15, and handled within hours. CBJ+raises the very interesting issue of higher-order patterns.+It turns out that some form of it is readily covered in+our setting.++-}++import Test.HUnit++import Data.Generics+++-- Sample datatypes+data T1 = T1a Int | T1b Float+ deriving (Show, Eq, Typeable, Data)+data T2 = T2a T1 T2 | T2b+ deriving (Show, Eq, Typeable, Data)++-- Eliminate a constructor if feasible+elim' :: (Data y, Data x) => Constr -> y -> Maybe x+elim' c y = if toConstr y == c+ then unwrap y+ else Nothing+++-- Unwrap a term; Return its single component+unwrap :: (Data y, Data x) => y -> Maybe x +unwrap y = case gmapQ (Nothing `mkQ` Just) y of+ [Just x] -> Just x+ _ -> Nothing+++-- Eliminate a constructor if feasible; 2nd try+elim :: forall x y. (Data y, Data x) => (x -> y) -> y -> Maybe x+elim c y = elim' (toConstr (c (undefined::x))) y+++-- Visit a data structure+visitor :: (Data x, Data y, Data z)+ => (x -> y) -> (x -> x) -> z -> z+visitor c f = everywhere (mkT g)+ where+ g y = case elim c y of+ Just x -> c (f x) + Nothing -> y+++-- Main function for testing+tests = ( ( elim' (toConstr t1a) t1a) :: Maybe Int+ , ( (elim' (toConstr t1a) t1b) :: Maybe Int+ , ( (elim T1a t1a) :: Maybe Int+ , ( (elim T1a t1b) :: Maybe Int+ , ( (visitor T1a ((+) 46) t2) :: T2+ ))))) ~=? output+ where+ t1a = T1a 42+ t1b = T1b 3.14+ t2 = T2a t1a (T2a t1a T2b)+ output = (Just 42,(Nothing,(Just 42,(Nothing,T2a (T1a 88) (T2a (T1a 88) T2b)))))
tests/Labels.hs view
@@ -1,30 +1,30 @@-{-# OPTIONS -fglasgow-exts #-} - -module Labels (tests) where - --- This module tests availability of field labels. - -import Test.HUnit - -import Data.Generics - --- A datatype without labels -data NoLabels = NoLabels Int Float - deriving (Typeable, Data) - --- A datatype with labels -data YesLabels = YesLabels { myint :: Int - , myfloat :: Float - } - deriving (Typeable, Data) - --- Test terms -noLabels = NoLabels 42 3.14 -yesLabels = YesLabels 42 3.14 - --- Main function for testing -tests = ( constrFields $ toConstr noLabels - , constrFields $ toConstr yesLabels - ) ~=? output - -output = ([],["myint","myfloat"]) +{-# OPTIONS -fglasgow-exts #-}++module Labels (tests) where++-- This module tests availability of field labels.++import Test.HUnit++import Data.Generics++-- A datatype without labels+data NoLabels = NoLabels Int Float+ deriving (Typeable, Data)++-- A datatype with labels+data YesLabels = YesLabels { myint :: Int+ , myfloat :: Float+ }+ deriving (Typeable, Data)++-- Test terms+noLabels = NoLabels 42 3.14+yesLabels = YesLabels 42 3.14++-- Main function for testing+tests = ( constrFields $ toConstr noLabels+ , constrFields $ toConstr yesLabels+ ) ~=? output++output = ([],["myint","myfloat"])
tests/LocalQuantors.hs view
@@ -1,21 +1,21 @@-{-# OPTIONS -fglasgow-exts #-} - -module LocalQuantors () where - --- A datatype with a locally quantified component --- Seems to be too polymorphic to descend into structure! --- Largely irrelevant?! - -import Data.Generics - -data Test = Test (GenericT) deriving Typeable - -instance Data Test - where - gfoldl _ z x = z x -- folding without descent - toConstr (Test _) = testConstr - gunfold _ _ = error "gunfold" - dataTypeOf _ = testDataType - -testConstr = mkConstr testDataType "Test" [] Prefix -testDataType = mkDataType "Main.Test" [testConstr] +{-# OPTIONS -fglasgow-exts #-}++module LocalQuantors () where++-- A datatype with a locally quantified component+-- Seems to be too polymorphic to descend into structure!+-- Largely irrelevant?!++import Data.Generics++data Test = Test (GenericT) deriving Typeable++instance Data Test+ where+ gfoldl _ z x = z x -- folding without descent + toConstr (Test _) = testConstr+ gunfold _ _ = error "gunfold"+ dataTypeOf _ = testDataType++testConstr = mkConstr testDataType "Test" [] Prefix+testDataType = mkDataType "Main.Test" [testConstr]
tests/Main.hs view
@@ -1,82 +1,82 @@- -module Main where - -import Test.HUnit -import System.Exit - -import qualified Bits -import qualified Builders -import qualified Datatype -import qualified Ext1 -import qualified Ext2 -import qualified FoldTree -import qualified FreeNames -import qualified GEq -import qualified GMapQAssoc -import qualified GRead -import qualified GShow -import qualified GShow2 -import qualified GZip -import qualified GenUpTo -import qualified GetC -import qualified HList -import qualified HOPat -import qualified Labels -import qualified Newtype -import qualified Paradise -import qualified Perm -import qualified Reify -import qualified Strings -import qualified Tree -import qualified Twin -import qualified Typecase1 -import qualified Typecase2 -import qualified Where -import qualified XML - -import qualified Encode -- no tests, should compile -import qualified Ext -- no tests, should compile -import qualified GRead2 -- no tests, should compile -import qualified LocalQuantors -- no tests, should compile -import qualified NestedDatatypes -- no tests, should compile -import qualified Polymatch -- no tests, should compile - - -tests = - "All" ~: [ Datatype.tests - , FoldTree.tests - , GetC.tests - , GMapQAssoc.tests - , GRead.tests - , GShow.tests - , GShow2.tests - , HList.tests - , HOPat.tests - , Labels.tests - , Newtype.tests - , Perm.tests - , Twin.tests - , Typecase1.tests - , Typecase2.tests - , Where.tests - , XML.tests - , Tree.tests - , Strings.tests - , Reify.tests - , Paradise.tests - , GZip.tests - , GEq.tests - , GenUpTo.tests - , FreeNames.tests - , Ext1.tests - , Ext2.tests - , Bits.tests - , Builders.tests - ] - -main = do - putStrLn "Running tests for syb..." - counts <- runTestTT tests - if (failures counts > 0) - then exitFailure - else exitSuccess ++module Main where++import Test.HUnit+import System.Exit++import qualified Bits+import qualified Builders+import qualified Datatype+import qualified Ext1+import qualified Ext2+import qualified FoldTree+import qualified FreeNames+import qualified GEq+import qualified GMapQAssoc+import qualified GRead+import qualified GShow+import qualified GShow2+import qualified GZip+import qualified GenUpTo+import qualified GetC+import qualified HList+import qualified HOPat+import qualified Labels+import qualified Newtype+import qualified Paradise+import qualified Perm+import qualified Reify+import qualified Strings+import qualified Tree+import qualified Twin+import qualified Typecase1+import qualified Typecase2+import qualified Where+import qualified XML++import qualified Encode -- no tests, should compile+import qualified Ext -- no tests, should compile+import qualified GRead2 -- no tests, should compile+import qualified LocalQuantors -- no tests, should compile+import qualified NestedDatatypes -- no tests, should compile+import qualified Polymatch -- no tests, should compile+++tests =+ "All" ~: [ Datatype.tests+ , FoldTree.tests+ , GetC.tests+ , GMapQAssoc.tests+ , GRead.tests+ , GShow.tests+ , GShow2.tests+ , HList.tests+ , HOPat.tests+ , Labels.tests+ , Newtype.tests+ , Perm.tests+ , Twin.tests+ , Typecase1.tests+ , Typecase2.tests+ , Where.tests+ , XML.tests+ , Tree.tests+ , Strings.tests+ , Reify.tests+ , Paradise.tests+ , GZip.tests+ , GEq.tests+ , GenUpTo.tests+ , FreeNames.tests+ , Ext1.tests+ , Ext2.tests+ , Bits.tests+ , Builders.tests+ ]++main = do+ putStrLn "Running tests for syb..."+ counts <- runTestTT tests+ if (failures counts > 0)+ then exitFailure+ else exitSuccess
tests/NestedDatatypes.hs view
@@ -1,43 +1,43 @@-{-# OPTIONS -fglasgow-exts #-} -{-# LANGUAGE UndecidableInstances #-} -{-# LANGUAGE DeriveDataTypeable #-} - -module NestedDatatypes () where - -{- - -We provide an illustrative ScrapYourBoilerplate example for a nested -datatype. For clarity, we do not derive the Typeable and Data -instances by the deriving mechanism but we show the intended -definitions. The overall conclusion is that nested datatypes do not -pose any challenge for the ScrapYourBoilerplate scheme. Well, this is -maybe not quite true because it seems like we need to allow -undecidable instances. - --} - -import Data.Dynamic -import Data.Generics - - --- A nested datatype -data Nest a = Box a | Wrap (Nest [a]) deriving Typeable - - --- The Data instance for the nested datatype -instance (Data a, Data [a]) => Data (Nest a) - where - gfoldl k z (Box a) = z Box `k` a - gfoldl k z (Wrap w) = z Wrap `k` w - gmapT f (Box a) = Box (f a) - gmapT f (Wrap w) = Wrap (f w) - toConstr (Box _) = boxConstr - toConstr (Wrap _) = wrapConstr - gunfold k z c = case constrIndex c of - 1 -> k (z Box) - 2 -> k (z Wrap) - dataTypeOf _ = nestDataType - -boxConstr = mkConstr nestDataType "Box" [] Prefix -wrapConstr = mkConstr nestDataType "Wrap" [] Prefix -nestDataType = mkDataType "Main.Nest" [boxConstr,wrapConstr] +{-# OPTIONS -fglasgow-exts #-}+{-# LANGUAGE UndecidableInstances #-}+{-# LANGUAGE DeriveDataTypeable #-}++module NestedDatatypes () where++{-++We provide an illustrative ScrapYourBoilerplate example for a nested+datatype. For clarity, we do not derive the Typeable and Data+instances by the deriving mechanism but we show the intended+definitions. The overall conclusion is that nested datatypes do not+pose any challenge for the ScrapYourBoilerplate scheme. Well, this is+maybe not quite true because it seems like we need to allow+undecidable instances.++-}++import Data.Dynamic+import Data.Generics++ +-- A nested datatype+data Nest a = Box a | Wrap (Nest [a]) deriving Typeable+++-- The Data instance for the nested datatype+instance (Data a, Data [a]) => Data (Nest a)+ where+ gfoldl k z (Box a) = z Box `k` a+ gfoldl k z (Wrap w) = z Wrap `k` w+ gmapT f (Box a) = Box (f a)+ gmapT f (Wrap w) = Wrap (f w)+ toConstr (Box _) = boxConstr+ toConstr (Wrap _) = wrapConstr+ gunfold k z c = case constrIndex c of+ 1 -> k (z Box)+ 2 -> k (z Wrap)+ dataTypeOf _ = nestDataType++boxConstr = mkConstr nestDataType "Box" [] Prefix+wrapConstr = mkConstr nestDataType "Wrap" [] Prefix+nestDataType = mkDataType "Main.Nest" [boxConstr,wrapConstr]
tests/Newtype.hs view
@@ -1,20 +1,20 @@-{-# LANGUAGE CPP #-} -{-# OPTIONS -fglasgow-exts #-} - -module Newtype (tests) where - --- The type of a newtype should treat the newtype as opaque - -import Test.HUnit - -import Data.Generics - -newtype T = MkT Int deriving( Typeable ) - -tests = show (typeOf (undefined :: T)) ~?= output - -#if __GLASGOW_HASKELL__ >= 701 -output = "T" -#else -output = "Newtype.T" -#endif +{-# LANGUAGE CPP #-}+{-# OPTIONS -fglasgow-exts #-}++module Newtype (tests) where++-- The type of a newtype should treat the newtype as opaque++import Test.HUnit++import Data.Generics++newtype T = MkT Int deriving( Typeable )++tests = show (typeOf (undefined :: T)) ~?= output++#if __GLASGOW_HASKELL__ >= 701+output = "T"+#else+output = "Newtype.T"+#endif
tests/Paradise.hs view
@@ -1,29 +1,29 @@-{-# OPTIONS -fglasgow-exts #-} - -module Paradise (tests) where - -{- - -This test runs the infamous PARADISE benchmark, -which is the HELLO WORLD example of generic programming, -i.e., the "increase salary" function is applied to -a typical company just as shown in the boilerplate paper. - --} - -import Test.HUnit - -import Data.Generics -import CompanyDatatypes - --- Increase salary by percentage -increase :: Float -> Company -> Company -increase k = everywhere (mkT (incS k)) - --- "interesting" code for increase -incS :: Float -> Salary -> Salary -incS k (S s) = S (s * (1+k)) - -tests = increase 0.1 genCom ~=? output - -output = C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8800.0)) [PU (E (P "Joost" "Amsterdam") (S 1100.0)),PU (E (P "Marlow" "Cambridge") (S 2200.0))],D "Strategy" (E (P "Blair" "London") (S 110000.0)) []] +{-# OPTIONS -fglasgow-exts #-}++module Paradise (tests) where++{-++This test runs the infamous PARADISE benchmark,+which is the HELLO WORLD example of generic programming,+i.e., the "increase salary" function is applied to+a typical company just as shown in the boilerplate paper.++-}++import Test.HUnit++import Data.Generics+import CompanyDatatypes++-- Increase salary by percentage+increase :: Float -> Company -> Company+increase k = everywhere (mkT (incS k))++-- "interesting" code for increase+incS :: Float -> Salary -> Salary+incS k (S s) = S (s * (1+k))++tests = increase 0.1 genCom ~=? output++output = C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8800.0)) [PU (E (P "Joost" "Amsterdam") (S 1100.0)),PU (E (P "Marlow" "Cambridge") (S 2200.0))],D "Strategy" (E (P "Blair" "London") (S 110000.0)) []]
tests/Perm.hs view
@@ -1,139 +1,139 @@-{-# OPTIONS -fglasgow-exts #-} - -module Perm (tests) where - -{- - -This module illustrates permutation phrases. -Disclaimer: this is a perhaps naive, certainly undebugged example. - --} - -import Test.HUnit - -import Control.Applicative (Alternative(..), Applicative(..)) -import Control.Monad -import Data.Generics - ---------------------------------------------------------------------------- --- We want to read terms of type T3 regardless of the order T1 and T2. ---------------------------------------------------------------------------- - -data T1 = T1 deriving (Show, Eq, Typeable, Data) -data T2 = T2 deriving (Show, Eq, Typeable, Data) -data T3 = T3 T1 T2 deriving (Show, Eq, Typeable, Data) - - ---------------------------------------------------------------------------- --- A silly monad that we use to read lists of constructor strings. ---------------------------------------------------------------------------- - --- Type constructor -newtype ReadT a = ReadT { unReadT :: [String] -> Maybe ([String],a) } - - - --- Run a computation -runReadT x y = case unReadT x y of - Just ([],y) -> Just y - _ -> Nothing - --- Read one string -readT :: ReadT String -readT = ReadT (\x -> if null x - then Nothing - else Just (tail x, head x) - ) - -instance Functor ReadT where - fmap = liftM - -instance Applicative ReadT where - pure = return - (<*>) = ap - -instance Alternative ReadT where - (<|>) = mplus - empty = mzero - --- ReadT is a monad! -instance Monad ReadT where - return x = ReadT (\y -> Just (y,x)) - c >>= f = ReadT (\x -> case unReadT c x of - Nothing -> Nothing - Just (x', a) -> unReadT (f a) x' - ) - --- ReadT also accommodates mzero and mplus! -instance MonadPlus ReadT where - mzero = ReadT (const Nothing) - f `mplus` g = ReadT (\x -> case unReadT f x of - Nothing -> unReadT g x - y -> y - ) - - ---------------------------------------------------------------------------- --- A helper type to appeal to predicative type system. ---------------------------------------------------------------------------- - -newtype GenM = GenM { unGenM :: forall a. Data a => a -> ReadT a } - - ---------------------------------------------------------------------------- --- The function that reads and copes with all permutations. ---------------------------------------------------------------------------- - -buildT :: forall a. Data a => ReadT a -buildT = result - - where - result = do str <- readT - con <- string2constr str - ske <- return $ fromConstr con - fs <- return $ gmapQ buildT' ske - perm [] fs ske - - -- Determine type of data to be constructed - myType = myTypeOf result - where - myTypeOf :: forall a. ReadT a -> a - myTypeOf = undefined - - -- Turn string into constructor - string2constr str = maybe mzero - return - (readConstr (dataTypeOf myType) str) - - -- Specialise buildT per kid type - buildT' :: forall a. Data a => a -> GenM - buildT' (_::a) = GenM (const mzero `extM` const (buildT::ReadT a)) - - -- The permutation exploration function - perm :: forall a. Data a => [GenM] -> [GenM] -> a -> ReadT a - perm [] [] a = return a - perm fs [] a = perm [] fs a - perm fs (f:fs') a = ( - do a' <- gmapMo (unGenM f) a - perm fs fs' a' - ) - `mplus` - ( - do guard (not (null fs')) - perm (f:fs) fs' a - ) - - ---------------------------------------------------------------------------- --- The main function for testing ---------------------------------------------------------------------------- - -tests = - ( runReadT buildT ["T1"] :: Maybe T1 -- should parse fine - , ( runReadT buildT ["T2"] :: Maybe T2 -- should parse fine - , ( runReadT buildT ["T3","T1","T2"] :: Maybe T3 -- should parse fine - , ( runReadT buildT ["T3","T2","T1"] :: Maybe T3 -- should parse fine - , ( runReadT buildT ["T3","T2","T2"] :: Maybe T3 -- should fail - ))))) ~=? output - -output = (Just T1,(Just T2,(Just (T3 T1 T2),(Just (T3 T1 T2),Nothing)))) +{-# OPTIONS -fglasgow-exts #-}++module Perm (tests) where++{-++This module illustrates permutation phrases.+Disclaimer: this is a perhaps naive, certainly undebugged example.++-}++import Test.HUnit++import Control.Applicative (Alternative(..), Applicative(..))+import Control.Monad+import Data.Generics++---------------------------------------------------------------------------+-- We want to read terms of type T3 regardless of the order T1 and T2.+---------------------------------------------------------------------------++data T1 = T1 deriving (Show, Eq, Typeable, Data)+data T2 = T2 deriving (Show, Eq, Typeable, Data)+data T3 = T3 T1 T2 deriving (Show, Eq, Typeable, Data)+++---------------------------------------------------------------------------+-- A silly monad that we use to read lists of constructor strings.+---------------------------------------------------------------------------++-- Type constructor+newtype ReadT a = ReadT { unReadT :: [String] -> Maybe ([String],a) }++++-- Run a computation+runReadT x y = case unReadT x y of+ Just ([],y) -> Just y+ _ -> Nothing++-- Read one string+readT :: ReadT String+readT = ReadT (\x -> if null x+ then Nothing+ else Just (tail x, head x)+ )++instance Functor ReadT where+ fmap = liftM++instance Applicative ReadT where+ pure = return+ (<*>) = ap++instance Alternative ReadT where+ (<|>) = mplus+ empty = mzero++-- ReadT is a monad!+instance Monad ReadT where+ return x = ReadT (\y -> Just (y,x))+ c >>= f = ReadT (\x -> case unReadT c x of+ Nothing -> Nothing+ Just (x', a) -> unReadT (f a) x'+ )++-- ReadT also accommodates mzero and mplus!+instance MonadPlus ReadT where+ mzero = ReadT (const Nothing)+ f `mplus` g = ReadT (\x -> case unReadT f x of+ Nothing -> unReadT g x+ y -> y+ )+++---------------------------------------------------------------------------+-- A helper type to appeal to predicative type system.+---------------------------------------------------------------------------++newtype GenM = GenM { unGenM :: forall a. Data a => a -> ReadT a }+++---------------------------------------------------------------------------+-- The function that reads and copes with all permutations.+---------------------------------------------------------------------------++buildT :: forall a. Data a => ReadT a+buildT = result++ where+ result = do str <- readT+ con <- string2constr str+ ske <- return $ fromConstr con+ fs <- return $ gmapQ buildT' ske+ perm [] fs ske++ -- Determine type of data to be constructed+ myType = myTypeOf result+ where+ myTypeOf :: forall a. ReadT a -> a+ myTypeOf = undefined++ -- Turn string into constructor+ string2constr str = maybe mzero+ return+ (readConstr (dataTypeOf myType) str)++ -- Specialise buildT per kid type+ buildT' :: forall a. Data a => a -> GenM+ buildT' (_::a) = GenM (const mzero `extM` const (buildT::ReadT a))++ -- The permutation exploration function+ perm :: forall a. Data a => [GenM] -> [GenM] -> a -> ReadT a+ perm [] [] a = return a+ perm fs [] a = perm [] fs a+ perm fs (f:fs') a = (+ do a' <- gmapMo (unGenM f) a+ perm fs fs' a'+ )+ `mplus`+ (+ do guard (not (null fs'))+ perm (f:fs) fs' a+ )+++---------------------------------------------------------------------------+-- The main function for testing+---------------------------------------------------------------------------++tests =+ ( runReadT buildT ["T1"] :: Maybe T1 -- should parse fine+ , ( runReadT buildT ["T2"] :: Maybe T2 -- should parse fine+ , ( runReadT buildT ["T3","T1","T2"] :: Maybe T3 -- should parse fine+ , ( runReadT buildT ["T3","T2","T1"] :: Maybe T3 -- should parse fine+ , ( runReadT buildT ["T3","T2","T2"] :: Maybe T3 -- should fail+ ))))) ~=? output++output = (Just T1,(Just T2,(Just (T3 T1 T2),(Just (T3 T1 T2),Nothing))))
tests/Polymatch.hs view
@@ -1,70 +1,70 @@-{-# OPTIONS -fglasgow-exts #-} - -module Polymatch () where - - -import Data.Typeable -import Data.Generics - - --- Representation of kids -kids x = gmapQ Kid x -- get all kids -type Kids = [Kid] -data Kid = forall k. Typeable k => Kid k - - --- Build term from a list of kids and the constructor -fromConstrL :: Data a => Kids -> Constr -> Maybe a -fromConstrL l = unIDL . gunfold k z - where - z c = IDL (Just c) l - k (IDL Nothing _) = IDL Nothing undefined - k (IDL (Just f) (Kid x:l)) = IDL f' l - where - f' = case cast x of - (Just x') -> Just (f x') - _ -> Nothing - - --- Helper datatype -data IDL x = IDL (Maybe x) Kids -unIDL (IDL mx _) = mx - - --- Two sample datatypes -data A = A String deriving (Read, Show, Eq, Data, Typeable) -data B = B String deriving (Read, Show, Eq, Data, Typeable) - - --- Mediate between two "left-equal" Either types -f :: (Data a, Data b, Show a, Read b) - => (a->b) -> Either String a -> Either String b - -f g (Right a) = Right $ g a -- conversion really needed --- f g (Left s) = Left s -- unappreciated conversion --- f g s = s -- doesn't typecheck --- f g s = deep_rebuild s -- too expensive -f g s = just (shallow_rebuild s) -- perhaps this is Ok? - - --- Get rid of maybies -just = maybe (error "tried, but failed.") id - - --- Just mentioned for completeness' sake -deep_rebuild :: (Show a, Read b) => a -> b -deep_rebuild = read . show - - --- For the record: it's possible. -shallow_rebuild :: (Data a, Data b) => a -> Maybe b -shallow_rebuild a = b - where - b = fromConstrL (kids a) constr - constr = indexConstr (dataTypeOf b) (constrIndex (toConstr a)) - - --- Test cases -a2b (A s) = B s -- silly conversion -t1 = f a2b (Left "x") -- prints Left "x" -t2 = f a2b (Right (A "y")) -- prints Right (B "y") +{-# OPTIONS -fglasgow-exts #-}++module Polymatch () where+++import Data.Typeable+import Data.Generics+++-- Representation of kids+kids x = gmapQ Kid x -- get all kids+type Kids = [Kid]+data Kid = forall k. Typeable k => Kid k+++-- Build term from a list of kids and the constructor +fromConstrL :: Data a => Kids -> Constr -> Maybe a+fromConstrL l = unIDL . gunfold k z+ where+ z c = IDL (Just c) l+ k (IDL Nothing _) = IDL Nothing undefined+ k (IDL (Just f) (Kid x:l)) = IDL f' l+ where+ f' = case cast x of+ (Just x') -> Just (f x')+ _ -> Nothing+++-- Helper datatype+data IDL x = IDL (Maybe x) Kids+unIDL (IDL mx _) = mx+++-- Two sample datatypes+data A = A String deriving (Read, Show, Eq, Data, Typeable)+data B = B String deriving (Read, Show, Eq, Data, Typeable)+++-- Mediate between two "left-equal" Either types+f :: (Data a, Data b, Show a, Read b)+ => (a->b) -> Either String a -> Either String b++f g (Right a) = Right $ g a -- conversion really needed+-- f g (Left s) = Left s -- unappreciated conversion+-- f g s = s -- doesn't typecheck +-- f g s = deep_rebuild s -- too expensive+f g s = just (shallow_rebuild s) -- perhaps this is Ok?+++-- Get rid of maybies+just = maybe (error "tried, but failed.") id+++-- Just mentioned for completeness' sake+deep_rebuild :: (Show a, Read b) => a -> b+deep_rebuild = read . show+++-- For the record: it's possible.+shallow_rebuild :: (Data a, Data b) => a -> Maybe b+shallow_rebuild a = b + where+ b = fromConstrL (kids a) constr+ constr = indexConstr (dataTypeOf b) (constrIndex (toConstr a))+++-- Test cases+a2b (A s) = B s -- silly conversion+t1 = f a2b (Left "x") -- prints Left "x"+t2 = f a2b (Right (A "y")) -- prints Right (B "y")
tests/Reify.hs view
@@ -1,413 +1,413 @@-{-# OPTIONS -fglasgow-exts #-} - -module Reify (tests) where - -{- - -The following examples illustrate the reification facilities for type -structure. Most notably, we generate shallow terms using the depth of -types and constructors as means to steer the generation. - --} - -import Test.HUnit - -import Data.Maybe -import Data.Generics -import Control.Monad.State -import CompanyDatatypes - - - ------------------------------------------------------------------------------- --- --- Encoding types as values; some other way. --- ------------------------------------------------------------------------------- - -{- - -This group provides a style of encoding types as values and using -them. This style is seen as an alternative to the pragmatic style used -in Data.Typeable.typeOf and elsewhere, i.e., simply use an "undefined" -to denote a type argument. This pragmatic style suffers from lack -of robustness: one feels tempted to pattern match on undefineds. -Maybe Data.Typeable.typeOf etc. should be rewritten accordingly. - --} - - --- | Type as values to stipulate use of undefineds -type TypeVal a = a -> () - - --- | The value that denotes a type -typeVal :: TypeVal a -typeVal = const () - - --- | Test for type equivalence -sameType :: (Typeable a, Typeable b) => TypeVal a -> TypeVal b -> Bool -sameType tva tvb = typeOf (type2val tva) == - typeOf (type2val tvb) - - --- | Map a value to its type -val2type :: a -> TypeVal a -val2type _ = typeVal - - --- | Stipulate this idiom! -type2val :: TypeVal a -> a -type2val _ = undefined - - --- | Constrain a type -withType :: a -> TypeVal a -> a -withType x _ = x - - --- | The argument type of a function -argType :: (a -> b) -> TypeVal a -argType _ = typeVal - - --- | The result type of a function -resType :: (a -> b) -> TypeVal b -resType _ = typeVal - - --- | The parameter type of type constructor -paraType :: t a -> TypeVal a -paraType _ = typeVal - - --- Type functions, --- i.e., functions mapping types to values --- -type TypeFun a r = TypeVal a -> r - - - --- Generic type functions, --- i.e., functions mapping types to values --- -type GTypeFun r = forall a. Data a => TypeFun a r - - - --- | Extend a type function -extType :: (Data a, Typeable r) => GTypeFun r -> TypeFun a r -> GTypeFun r -extType f x = maybe f id (cast x) - - - ------------------------------------------------------------------------------- --- --- Mapping operators to map over type structure --- ------------------------------------------------------------------------------- - - --- | Query all constructors of a given type - -gmapType :: ([(Constr,r')] -> r) - -> GTypeFun (Constr -> r') - -> GTypeFun r - -gmapType (o::[(Constr,r')] -> r) f (t::TypeVal a) - = - o $ zip cons query - - where - - -- All constructors of the given type - cons :: [Constr] - cons = if isAlgType $ dataTypeOf $ type2val t - then dataTypeConstrs $ dataTypeOf $ type2val t - else [] - - -- Query constructors - query :: [r'] - query = map (f t) cons - - --- | Query all subterm types of a given constructor - -gmapConstr :: ([r] -> r') - -> GTypeFun r - -> GTypeFun (Constr -> r') - -gmapConstr (o::[r] -> r') f (t::TypeVal a) c - = - o $ query - - where - - -- Term for the given constructor - term :: a - term = fromConstr c - - -- Query subterm types - query :: [r] - query = gmapQ (f . val2type) term - - --- | Compute arity of a given constructor -constrArity :: GTypeFun (Constr -> Int) -constrArity t c = glength $ withType (fromConstr c) t - - --- | Query all immediate subterm types of a given type -gmapSubtermTypes :: (Data a, Typeable r) - => (r -> r -> r) -> r -> GTypeFun r -> TypeVal a -> r -gmapSubtermTypes o (r::r) f (t::TypeVal a) - = - reduce (concat (map (gmapQ (query . val2type)) terms)) - (GTypeFun' f) - - where - - -- All constructors of the given type - cons :: [Constr] - cons = if isAlgType $ dataTypeOf $ type2val t - then dataTypeConstrs $ dataTypeOf $ type2val t - else [] - - -- Terms for all constructors - terms :: [a] - terms = map fromConstr cons - - -- Query a subterm type - query :: Data b => TypeVal b -> GTypeFun' r -> (r,GTypeFun' r) - query t f = (unGTypeFun' f t, GTypeFun' (disable t (unGTypeFun' f))) - - -- Constant out given type - disable :: Data b => TypeVal b -> GTypeFun r -> GTypeFun r - disable (t::TypeVal b) f = f `extType` \(_::TypeVal b) -> r - - -- Reduce all subterm types - reduce :: [GTypeFun' r -> (r,GTypeFun' r)] -> GTypeFun' r -> r - reduce [] _ = r - reduce (xy:z) g = fst (xy g) `o` reduce z (snd (xy g)) - - --- First-class polymorphic variation on GTypeFun -newtype GTypeFun' r = GTypeFun' (GTypeFun r) -unGTypeFun' (GTypeFun' f) = f - - --- | Query all immediate subterm types. --- There is an extra argument to \"constant out\" the type at hand. --- This can be used to avoid cycles. - -gmapSubtermTypesConst :: (Data a, Typeable r) - => (r -> r -> r) - -> r - -> GTypeFun r - -> TypeVal a - -> r -gmapSubtermTypesConst o (r::r) f (t::TypeVal a) - = - gmapSubtermTypes o r f' t - where - f' :: GTypeFun r - f' = f `extType` \(_::TypeVal a) -> r - - --- Count all distinct subterm types -gcountSubtermTypes :: Data a => TypeVal a -> Int -gcountSubtermTypes = gmapSubtermTypes (+) (0::Int) (const 1) - - --- | A simplied variation on gmapSubtermTypes. --- Weakness: no awareness of doubles. --- Strength: easy to comprehend as it uses gmapType and gmapConstr. - -_gmapSubtermTypes :: (Data a, Typeable r) - => (r -> r -> r) -> r -> GTypeFun r -> TypeVal a -> r -_gmapSubtermTypes o (r::r) f - = - gmapType otype (gmapConstr oconstr f) - - where - - otype :: [(Constr,r)] -> r - otype = foldr (\x y -> snd x `o` y) r - - oconstr :: [r] -> r - oconstr = foldr o r - - ------------------------------------------------------------------------------- --- --- Some reifying relations on types --- ------------------------------------------------------------------------------- - - --- | Reachability relation on types, i.e., --- test if nodes of type @a@ are reachable from nodes of type @b@. --- The relation is defined to be reflexive. - -reachableType :: (Data a, Data b) => TypeVal a -> TypeVal b -> Bool -reachableType (a::TypeVal a) (b::TypeVal b) - = - or [ sameType a b - , gmapSubtermTypesConst (\x y -> or [x,y]) False (reachableType a) b - ] - - --- | Depth of a datatype as the constructor with the minimum depth. --- The outermost 'Nothing' denotes a type without constructors. --- The innermost 'Nothing' denotes potentially infinite. - -depthOfType :: GTypeFun Bool -> GTypeFun (Maybe (Constr, Maybe Int)) -depthOfType p (t::TypeVal a) - = - gmapType o f t - - where - - o :: [(Constr, Maybe Int)] -> Maybe (Constr, Maybe Int) - o l = if null l then Nothing else Just (foldr1 min' l) - - f :: GTypeFun (Constr -> Maybe Int) - f = depthOfConstr p' - - -- Specific minimum operator - min' :: (Constr, Maybe Int) -> (Constr, Maybe Int) -> (Constr, Maybe Int) - min' x (_, Nothing) = x - min' (_, Nothing) x = x - min' (c, Just i) (c', Just i') | i <= i' = (c, Just i) - min' (c, Just i) (c', Just i') = (c', Just i') - - -- Updated predicate for unblocked types - p' :: GTypeFun Bool - p' = p `extType` \(_::TypeVal a) -> False - - --- | Depth of a constructor. --- Depth is viewed as the maximum depth of all subterm types + 1. --- 'Nothing' denotes potentially infinite. - -depthOfConstr :: GTypeFun Bool -> GTypeFun (Constr -> Maybe Int) -depthOfConstr p (t::TypeVal a) c - = - gmapConstr o f t c - - where - - o :: [Maybe Int] -> Maybe Int - o = inc' . foldr max' (Just 0) - - f :: GTypeFun (Maybe Int) - f t' = if p t' - then - case depthOfType p t' of - Nothing -> Just 0 - Just (_, x) -> x - else Nothing - - -- Specific maximum operator - max' Nothing _ = Nothing - max' _ Nothing = Nothing - max' (Just i) (Just i') | i >= i' = Just i - max' (Just i) (Just i') = Just i' - - -- Specific increment operator - inc' Nothing = Nothing - inc' (Just i) = Just (i+1) - - ------------------------------------------------------------------------------- --- --- Build a shallow term --- ------------------------------------------------------------------------------- - -shallowTerm :: (forall a. Data a => Maybe a) -> (forall b. Data b => b) -shallowTerm cust - = result - where - result :: forall b. Data b => b - -- Need a type signature here to bring 'b' into scope - result = maybe gdefault id cust - where - - -- The worker, also used for type disambiguation - gdefault :: b - gdefault = case con of - Just (con, Just _) -> fromConstrB (shallowTerm cust) con - _ -> error "no shallow term!" - - -- The type to be constructed - typeVal :: TypeVal b - typeVal = val2type gdefault - - -- The most shallow constructor if any - con :: Maybe (Constr, Maybe Int) - con = depthOfType (const True) typeVal - - - --- For testing shallowTerm -shallowTermBase :: GenericR Maybe -shallowTermBase = Nothing - `extR` Just (1.23::Float) - `extR` Just ("foo"::String) - - - --- Sample datatypes -data T1 = T1a deriving (Typeable, Data) -- just a constant -data T2 = T2 T1 deriving (Typeable, Data) -- little detour -data T3 = T3a T3 | T3b T2 deriving (Typeable, Data) -- recursive case -data T4 = T4 T3 T3 deriving (Typeable, Data) -- sum matters - - - --- Sample type arguments -t0 = typeVal :: TypeVal Int -t1 = typeVal :: TypeVal T1 -t2 = typeVal :: TypeVal T2 -t3 = typeVal :: TypeVal T3 -t4 = typeVal :: TypeVal T4 -tCompany = typeVal :: TypeVal Company -tPerson = typeVal :: TypeVal Person -tEmployee = typeVal :: TypeVal Employee -tDept = typeVal :: TypeVal Dept - - - --- Test cases -test0 = t1 `reachableType` t1 -- True -test1 = t1 `reachableType` t2 -- True -test2 = t2 `reachableType` t1 -- False -test3 = t1 `reachableType` t3 -test4 = tPerson `reachableType` tCompany -test5 = gcountSubtermTypes tPerson -test6 = gcountSubtermTypes tEmployee -test7 = gcountSubtermTypes tDept -test8 = shallowTerm shallowTermBase :: Person -test9 = shallowTerm shallowTermBase :: Employee -test10 = shallowTerm shallowTermBase :: Dept - - - -tests = ( test0 - , ( test1 - , ( test2 - , ( test3 - , ( test4 - , ( test5 - , ( test6 - , ( test7 - , ( test8 - , ( test9 - , ( test10 - ))))))))))) ~=? output - -output = (True,(True,(False,(True,(True,(1,(2,(3,(P "foo" "foo", - (E (P "foo" "foo") (S 1.23), - D "foo" (E (P "foo" "foo") (S 1.23)) [])))))))))) +{-# OPTIONS -fglasgow-exts #-}++module Reify (tests) where++{-++The following examples illustrate the reification facilities for type+structure. Most notably, we generate shallow terms using the depth of+types and constructors as means to steer the generation.++-}++import Test.HUnit++import Data.Maybe+import Data.Generics+import Control.Monad.State+import CompanyDatatypes++++------------------------------------------------------------------------------+--+-- Encoding types as values; some other way.+--+------------------------------------------------------------------------------++{-++This group provides a style of encoding types as values and using+them. This style is seen as an alternative to the pragmatic style used+in Data.Typeable.typeOf and elsewhere, i.e., simply use an "undefined"+to denote a type argument. This pragmatic style suffers from lack+of robustness: one feels tempted to pattern match on undefineds.+Maybe Data.Typeable.typeOf etc. should be rewritten accordingly.++-}+++-- | Type as values to stipulate use of undefineds+type TypeVal a = a -> ()+++-- | The value that denotes a type+typeVal :: TypeVal a+typeVal = const ()+++-- | Test for type equivalence+sameType :: (Typeable a, Typeable b) => TypeVal a -> TypeVal b -> Bool+sameType tva tvb = typeOf (type2val tva) ==+ typeOf (type2val tvb)+++-- | Map a value to its type+val2type :: a -> TypeVal a+val2type _ = typeVal+++-- | Stipulate this idiom!+type2val :: TypeVal a -> a+type2val _ = undefined+++-- | Constrain a type+withType :: a -> TypeVal a -> a+withType x _ = x+++-- | The argument type of a function+argType :: (a -> b) -> TypeVal a+argType _ = typeVal+++-- | The result type of a function+resType :: (a -> b) -> TypeVal b+resType _ = typeVal+++-- | The parameter type of type constructor+paraType :: t a -> TypeVal a+paraType _ = typeVal+++-- Type functions,+-- i.e., functions mapping types to values+--+type TypeFun a r = TypeVal a -> r++++-- Generic type functions,+-- i.e., functions mapping types to values+--+type GTypeFun r = forall a. Data a => TypeFun a r++++-- | Extend a type function+extType :: (Data a, Typeable r) => GTypeFun r -> TypeFun a r -> GTypeFun r+extType f x = maybe f id (cast x)++++------------------------------------------------------------------------------+--+-- Mapping operators to map over type structure+--+------------------------------------------------------------------------------+++-- | Query all constructors of a given type++gmapType :: ([(Constr,r')] -> r)+ -> GTypeFun (Constr -> r')+ -> GTypeFun r++gmapType (o::[(Constr,r')] -> r) f (t::TypeVal a)+ =+ o $ zip cons query++ where++ -- All constructors of the given type+ cons :: [Constr]+ cons = if isAlgType $ dataTypeOf $ type2val t+ then dataTypeConstrs $ dataTypeOf $ type2val t+ else []++ -- Query constructors+ query :: [r']+ query = map (f t) cons+++-- | Query all subterm types of a given constructor++gmapConstr :: ([r] -> r')+ -> GTypeFun r+ -> GTypeFun (Constr -> r')++gmapConstr (o::[r] -> r') f (t::TypeVal a) c+ =+ o $ query++ where++ -- Term for the given constructor+ term :: a+ term = fromConstr c++ -- Query subterm types+ query :: [r]+ query = gmapQ (f . val2type) term+++-- | Compute arity of a given constructor+constrArity :: GTypeFun (Constr -> Int)+constrArity t c = glength $ withType (fromConstr c) t+++-- | Query all immediate subterm types of a given type+gmapSubtermTypes :: (Data a, Typeable r)+ => (r -> r -> r) -> r -> GTypeFun r -> TypeVal a -> r+gmapSubtermTypes o (r::r) f (t::TypeVal a)+ =+ reduce (concat (map (gmapQ (query . val2type)) terms))+ (GTypeFun' f)++ where++ -- All constructors of the given type+ cons :: [Constr]+ cons = if isAlgType $ dataTypeOf $ type2val t+ then dataTypeConstrs $ dataTypeOf $ type2val t+ else []++ -- Terms for all constructors+ terms :: [a]+ terms = map fromConstr cons++ -- Query a subterm type+ query :: Data b => TypeVal b -> GTypeFun' r -> (r,GTypeFun' r)+ query t f = (unGTypeFun' f t, GTypeFun' (disable t (unGTypeFun' f)))++ -- Constant out given type+ disable :: Data b => TypeVal b -> GTypeFun r -> GTypeFun r+ disable (t::TypeVal b) f = f `extType` \(_::TypeVal b) -> r++ -- Reduce all subterm types+ reduce :: [GTypeFun' r -> (r,GTypeFun' r)] -> GTypeFun' r -> r+ reduce [] _ = r+ reduce (xy:z) g = fst (xy g) `o` reduce z (snd (xy g))+++-- First-class polymorphic variation on GTypeFun+newtype GTypeFun' r = GTypeFun' (GTypeFun r)+unGTypeFun' (GTypeFun' f) = f+++-- | Query all immediate subterm types.+-- There is an extra argument to \"constant out\" the type at hand.+-- This can be used to avoid cycles.++gmapSubtermTypesConst :: (Data a, Typeable r)+ => (r -> r -> r)+ -> r+ -> GTypeFun r+ -> TypeVal a+ -> r+gmapSubtermTypesConst o (r::r) f (t::TypeVal a)+ =+ gmapSubtermTypes o r f' t+ where+ f' :: GTypeFun r+ f' = f `extType` \(_::TypeVal a) -> r+++-- Count all distinct subterm types+gcountSubtermTypes :: Data a => TypeVal a -> Int+gcountSubtermTypes = gmapSubtermTypes (+) (0::Int) (const 1)+++-- | A simplied variation on gmapSubtermTypes.+-- Weakness: no awareness of doubles.+-- Strength: easy to comprehend as it uses gmapType and gmapConstr.++_gmapSubtermTypes :: (Data a, Typeable r)+ => (r -> r -> r) -> r -> GTypeFun r -> TypeVal a -> r+_gmapSubtermTypes o (r::r) f+ =+ gmapType otype (gmapConstr oconstr f)++ where++ otype :: [(Constr,r)] -> r+ otype = foldr (\x y -> snd x `o` y) r++ oconstr :: [r] -> r+ oconstr = foldr o r+++------------------------------------------------------------------------------+--+-- Some reifying relations on types+--+------------------------------------------------------------------------------+++-- | Reachability relation on types, i.e.,+-- test if nodes of type @a@ are reachable from nodes of type @b@.+-- The relation is defined to be reflexive.++reachableType :: (Data a, Data b) => TypeVal a -> TypeVal b -> Bool+reachableType (a::TypeVal a) (b::TypeVal b)+ =+ or [ sameType a b+ , gmapSubtermTypesConst (\x y -> or [x,y]) False (reachableType a) b+ ]+++-- | Depth of a datatype as the constructor with the minimum depth.+-- The outermost 'Nothing' denotes a type without constructors.+-- The innermost 'Nothing' denotes potentially infinite.++depthOfType :: GTypeFun Bool -> GTypeFun (Maybe (Constr, Maybe Int))+depthOfType p (t::TypeVal a)+ =+ gmapType o f t++ where++ o :: [(Constr, Maybe Int)] -> Maybe (Constr, Maybe Int)+ o l = if null l then Nothing else Just (foldr1 min' l)++ f :: GTypeFun (Constr -> Maybe Int)+ f = depthOfConstr p'++ -- Specific minimum operator+ min' :: (Constr, Maybe Int) -> (Constr, Maybe Int) -> (Constr, Maybe Int)+ min' x (_, Nothing) = x+ min' (_, Nothing) x = x+ min' (c, Just i) (c', Just i') | i <= i' = (c, Just i)+ min' (c, Just i) (c', Just i') = (c', Just i')++ -- Updated predicate for unblocked types+ p' :: GTypeFun Bool+ p' = p `extType` \(_::TypeVal a) -> False+++-- | Depth of a constructor.+-- Depth is viewed as the maximum depth of all subterm types + 1.+-- 'Nothing' denotes potentially infinite.++depthOfConstr :: GTypeFun Bool -> GTypeFun (Constr -> Maybe Int)+depthOfConstr p (t::TypeVal a) c+ =+ gmapConstr o f t c++ where++ o :: [Maybe Int] -> Maybe Int+ o = inc' . foldr max' (Just 0)++ f :: GTypeFun (Maybe Int)+ f t' = if p t'+ then+ case depthOfType p t' of+ Nothing -> Just 0+ Just (_, x) -> x+ else Nothing++ -- Specific maximum operator+ max' Nothing _ = Nothing+ max' _ Nothing = Nothing+ max' (Just i) (Just i') | i >= i' = Just i+ max' (Just i) (Just i') = Just i'++ -- Specific increment operator+ inc' Nothing = Nothing+ inc' (Just i) = Just (i+1)+++------------------------------------------------------------------------------+--+-- Build a shallow term+--+------------------------------------------------------------------------------++shallowTerm :: (forall a. Data a => Maybe a) -> (forall b. Data b => b)+shallowTerm cust+ = result+ where+ result :: forall b. Data b => b+ -- Need a type signature here to bring 'b' into scope+ result = maybe gdefault id cust+ where++ -- The worker, also used for type disambiguation+ gdefault :: b+ gdefault = case con of+ Just (con, Just _) -> fromConstrB (shallowTerm cust) con+ _ -> error "no shallow term!"++ -- The type to be constructed+ typeVal :: TypeVal b+ typeVal = val2type gdefault++ -- The most shallow constructor if any+ con :: Maybe (Constr, Maybe Int)+ con = depthOfType (const True) typeVal++++-- For testing shallowTerm+shallowTermBase :: GenericR Maybe+shallowTermBase = Nothing+ `extR` Just (1.23::Float)+ `extR` Just ("foo"::String)++++-- Sample datatypes+data T1 = T1a deriving (Typeable, Data) -- just a constant+data T2 = T2 T1 deriving (Typeable, Data) -- little detour+data T3 = T3a T3 | T3b T2 deriving (Typeable, Data) -- recursive case+data T4 = T4 T3 T3 deriving (Typeable, Data) -- sum matters++++-- Sample type arguments+t0 = typeVal :: TypeVal Int+t1 = typeVal :: TypeVal T1+t2 = typeVal :: TypeVal T2+t3 = typeVal :: TypeVal T3+t4 = typeVal :: TypeVal T4+tCompany = typeVal :: TypeVal Company+tPerson = typeVal :: TypeVal Person+tEmployee = typeVal :: TypeVal Employee+tDept = typeVal :: TypeVal Dept++++-- Test cases+test0 = t1 `reachableType` t1 -- True+test1 = t1 `reachableType` t2 -- True+test2 = t2 `reachableType` t1 -- False+test3 = t1 `reachableType` t3+test4 = tPerson `reachableType` tCompany+test5 = gcountSubtermTypes tPerson+test6 = gcountSubtermTypes tEmployee+test7 = gcountSubtermTypes tDept+test8 = shallowTerm shallowTermBase :: Person+test9 = shallowTerm shallowTermBase :: Employee+test10 = shallowTerm shallowTermBase :: Dept++++tests = ( test0+ , ( test1+ , ( test2+ , ( test3+ , ( test4+ , ( test5+ , ( test6+ , ( test7+ , ( test8+ , ( test9+ , ( test10+ ))))))))))) ~=? output++output = (True,(True,(False,(True,(True,(1,(2,(3,(P "foo" "foo",+ (E (P "foo" "foo") (S 1.23),+ D "foo" (E (P "foo" "foo") (S 1.23)) []))))))))))
tests/Strings.hs view
@@ -1,21 +1,21 @@-{-# OPTIONS -fglasgow-exts #-} - -module Strings (tests) where - -{- - -This test exercices GENERIC read, show, and eq for the company -datatypes which we use a lot. The output of the program should be -"True" which means that "gread" reads what "gshow" shows while the -read term is equal to the original term in terms of "geq". - --} - -import Test.HUnit - -import Data.Generics -import CompanyDatatypes - -tests = (case gread (gshow genCom) of - [(x,_)] -> geq genCom x - _ -> False) ~=? True +{-# OPTIONS -fglasgow-exts #-}++module Strings (tests) where++{-++This test exercices GENERIC read, show, and eq for the company+datatypes which we use a lot. The output of the program should be+"True" which means that "gread" reads what "gshow" shows while the+read term is equal to the original term in terms of "geq".++-}++import Test.HUnit++import Data.Generics+import CompanyDatatypes++tests = (case gread (gshow genCom) of+ [(x,_)] -> geq genCom x+ _ -> False) ~=? True
tests/Tree.hs view
@@ -1,62 +1,62 @@-{-# OPTIONS -fglasgow-exts #-} - -module Tree (tests) where - -{- - -This example illustrates serialisation and de-serialisation, -but we replace *series* by *trees* so to say. - --} - -import Test.HUnit - -import Control.Monad.Reader -import Data.Generics -import Data.Maybe -import Data.Tree -import CompanyDatatypes - - --- Trealise Data to Tree -data2tree :: Data a => a -> Tree String -data2tree = gdefault `extQ` atString - where - atString (x::String) = Node x [] - gdefault x = Node (showConstr (toConstr x)) (gmapQ data2tree x) - - --- De-trealise Tree to Data -tree2data :: Data a => Tree String -> Maybe a -tree2data = gdefault `extR` atString - where - atString (Node x []) = Just x - gdefault (Node x ts) = res - where - - -- a helper for type capture - res = maybe Nothing (kids . fromConstr) con - - -- the type to constructed - ta = fromJust res - - -- construct constructor - con = readConstr (dataTypeOf ta) x - - -- recursion per kid with accumulation - perkid ts = const (tail ts, tree2data (head ts)) - - -- recurse into kids - kids x = - do guard (glength x == length ts) - snd (gmapAccumM perkid ts x) - - --- Main function for testing -tests = ( genCom - , ( data2tree genCom - , ( (tree2data (data2tree genCom)) :: Maybe Company - , ( Just genCom == tree2data (data2tree genCom) - )))) ~=? output - -output = (C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8000.0)) [PU (E (P "Joost" "Amsterdam") (S 1000.0)),PU (E (P "Marlow" "Cambridge") (S 2000.0))],D "Strategy" (E (P "Blair" "London") (S 100000.0)) []],(Node {rootLabel = "C", subForest = [Node {rootLabel = "(:)", subForest = [Node {rootLabel = "D", subForest = [Node {rootLabel = "Research", subForest = []},Node {rootLabel = "E", subForest = [Node {rootLabel = "P", subForest = [Node {rootLabel = "Laemmel", subForest = []},Node {rootLabel = "Amsterdam", subForest = []}]},Node {rootLabel = "S", subForest = [Node {rootLabel = "8000.0", subForest = []}]}]},Node {rootLabel = "(:)", subForest = [Node {rootLabel = "PU", subForest = [Node {rootLabel = "E", subForest = [Node {rootLabel = "P", subForest = [Node {rootLabel = "Joost", subForest = []},Node {rootLabel = "Amsterdam", subForest = []}]},Node {rootLabel = "S", subForest = [Node {rootLabel = "1000.0", subForest = []}]}]}]},Node {rootLabel = "(:)", subForest = [Node {rootLabel = "PU", subForest = [Node {rootLabel = "E", subForest = [Node {rootLabel = "P", subForest = [Node {rootLabel = "Marlow", subForest = []},Node {rootLabel = "Cambridge", subForest = []}]},Node {rootLabel = "S", subForest = [Node {rootLabel = "2000.0", subForest = []}]}]}]},Node {rootLabel = "[]", subForest = []}]}]}]},Node {rootLabel = "(:)", subForest = [Node {rootLabel = "D", subForest = [Node {rootLabel = "Strategy", subForest = []},Node {rootLabel = "E", subForest = [Node {rootLabel = "P", subForest = [Node {rootLabel = "Blair", subForest = []},Node {rootLabel = "London", subForest = []}]},Node {rootLabel = "S", subForest = [Node {rootLabel = "100000.0", subForest = []}]}]},Node {rootLabel = "[]", subForest = []}]},Node {rootLabel = "[]", subForest = []}]}]}]},(Just (C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8000.0)) [PU (E (P "Joost" "Amsterdam") (S 1000.0)),PU (E (P "Marlow" "Cambridge") (S 2000.0))],D "Strategy" (E (P "Blair" "London") (S 100000.0)) []]),True))) +{-# OPTIONS -fglasgow-exts #-}++module Tree (tests) where++{-++This example illustrates serialisation and de-serialisation,+but we replace *series* by *trees* so to say.++-}++import Test.HUnit++import Control.Monad.Reader+import Data.Generics+import Data.Maybe+import Data.Tree+import CompanyDatatypes+++-- Trealise Data to Tree+data2tree :: Data a => a -> Tree String+data2tree = gdefault `extQ` atString+ where+ atString (x::String) = Node x []+ gdefault x = Node (showConstr (toConstr x)) (gmapQ data2tree x)+++-- De-trealise Tree to Data+tree2data :: Data a => Tree String -> Maybe a+tree2data = gdefault `extR` atString+ where+ atString (Node x []) = Just x+ gdefault (Node x ts) = res+ where++ -- a helper for type capture+ res = maybe Nothing (kids . fromConstr) con++ -- the type to constructed+ ta = fromJust res++ -- construct constructor+ con = readConstr (dataTypeOf ta) x++ -- recursion per kid with accumulation+ perkid ts = const (tail ts, tree2data (head ts)) ++ -- recurse into kids+ kids x =+ do guard (glength x == length ts)+ snd (gmapAccumM perkid ts x)+++-- Main function for testing+tests = ( genCom+ , ( data2tree genCom + , ( (tree2data (data2tree genCom)) :: Maybe Company + , ( Just genCom == tree2data (data2tree genCom)+ )))) ~=? output++output = (C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8000.0)) [PU (E (P "Joost" "Amsterdam") (S 1000.0)),PU (E (P "Marlow" "Cambridge") (S 2000.0))],D "Strategy" (E (P "Blair" "London") (S 100000.0)) []],(Node {rootLabel = "C", subForest = [Node {rootLabel = "(:)", subForest = [Node {rootLabel = "D", subForest = [Node {rootLabel = "Research", subForest = []},Node {rootLabel = "E", subForest = [Node {rootLabel = "P", subForest = [Node {rootLabel = "Laemmel", subForest = []},Node {rootLabel = "Amsterdam", subForest = []}]},Node {rootLabel = "S", subForest = [Node {rootLabel = "8000.0", subForest = []}]}]},Node {rootLabel = "(:)", subForest = [Node {rootLabel = "PU", subForest = [Node {rootLabel = "E", subForest = [Node {rootLabel = "P", subForest = [Node {rootLabel = "Joost", subForest = []},Node {rootLabel = "Amsterdam", subForest = []}]},Node {rootLabel = "S", subForest = [Node {rootLabel = "1000.0", subForest = []}]}]}]},Node {rootLabel = "(:)", subForest = [Node {rootLabel = "PU", subForest = [Node {rootLabel = "E", subForest = [Node {rootLabel = "P", subForest = [Node {rootLabel = "Marlow", subForest = []},Node {rootLabel = "Cambridge", subForest = []}]},Node {rootLabel = "S", subForest = [Node {rootLabel = "2000.0", subForest = []}]}]}]},Node {rootLabel = "[]", subForest = []}]}]}]},Node {rootLabel = "(:)", subForest = [Node {rootLabel = "D", subForest = [Node {rootLabel = "Strategy", subForest = []},Node {rootLabel = "E", subForest = [Node {rootLabel = "P", subForest = [Node {rootLabel = "Blair", subForest = []},Node {rootLabel = "London", subForest = []}]},Node {rootLabel = "S", subForest = [Node {rootLabel = "100000.0", subForest = []}]}]},Node {rootLabel = "[]", subForest = []}]},Node {rootLabel = "[]", subForest = []}]}]}]},(Just (C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8000.0)) [PU (E (P "Joost" "Amsterdam") (S 1000.0)),PU (E (P "Marlow" "Cambridge") (S 2000.0))],D "Strategy" (E (P "Blair" "London") (S 100000.0)) []]),True)))
tests/Twin.hs view
@@ -1,90 +1,90 @@-{-# OPTIONS -fglasgow-exts #-} - -module Twin (tests) where - -{- - -For the discussion in the 2nd boilerplate paper, -we favour some simplified development of twin traversal. -So the full general, stepwise story is in Data.Generics.Twin, -but the short version from the paper is turned into a test -case below. - -See the paper for an explanation. - --} - -import Test.HUnit - -import Data.Generics hiding (GQ,gzipWithQ,geq) - -geq' :: GenericQ (GenericQ Bool) -geq' x y = toConstr x == toConstr y - && and (gzipWithQ geq' x y) - -geq :: Data a => a -> a -> Bool -geq = geq' - -newtype GQ r = GQ (GenericQ r) - -gzipWithQ :: GenericQ (GenericQ r) - -> GenericQ (GenericQ [r]) -gzipWithQ f t1 t2 - = gApplyQ (gmapQ (\x -> GQ (f x)) t1) t2 - -gApplyQ :: Data a => [GQ r] -> a -> [r] -gApplyQ qs t = reverse (snd (gfoldlQ k z t)) - where - k :: ([GQ r], [r]) -> GenericQ ([GQ r], [r]) - k (GQ q : qs, rs) child = (qs, q child : rs) - z = (qs, []) - -newtype R r x = R { unR :: r } - -gfoldlQ :: (r -> GenericQ r) - -> r - -> GenericQ r - -gfoldlQ k z t = unR (gfoldl k' z' t) - where - z' _ = R z - k' (R r) c = R (k r c) - ------------------------------------------------------------------------------ - --- A dependently polymorphic geq -geq'' :: Data a => a -> a -> Bool -geq'' x y = toConstr x == toConstr y - && and (gzipWithQ' geq'' x y) - --- A helper type for existentially quantified queries -data XQ r = forall a. Data a => XQ (a -> r) - --- A dependently polymorphic gzipWithQ -gzipWithQ' :: (forall a. Data a => a -> a -> r) - -> (forall a. Data a => a -> a -> [r]) -gzipWithQ' f t1 t2 - = gApplyQ' (gmapQ (\x -> XQ (f x)) t1) t2 - --- Apply existentially quantified queries --- Insist on equal types! --- -gApplyQ' :: Data a => [XQ r] -> a -> [r] -gApplyQ' qs t = reverse (snd (gfoldlQ k z t)) - where - z = (qs, []) - k :: ([XQ r], [r]) -> GenericQ ([XQ r], [r]) - k (XQ q : qs, rs) child = (qs, q' child : rs) - where - q' = error "Twin mismatch" `extQ` q - - ------------------------------------------------------------------------------ - -tests = ( geq [True,True] [True,True] - , geq [True,True] [True,False] - , geq'' [True,True] [True,True] - , geq'' [True,True] [True,False] - ) ~=? output - -output = (True,False,True,False) +{-# OPTIONS -fglasgow-exts #-}+ +module Twin (tests) where++{-++For the discussion in the 2nd boilerplate paper,+we favour some simplified development of twin traversal.+So the full general, stepwise story is in Data.Generics.Twin,+but the short version from the paper is turned into a test+case below. ++See the paper for an explanation.+ +-}++import Test.HUnit++import Data.Generics hiding (GQ,gzipWithQ,geq)++geq' :: GenericQ (GenericQ Bool)+geq' x y = toConstr x == toConstr y+ && and (gzipWithQ geq' x y)++geq :: Data a => a -> a -> Bool+geq = geq'++newtype GQ r = GQ (GenericQ r)++gzipWithQ :: GenericQ (GenericQ r)+ -> GenericQ (GenericQ [r])+gzipWithQ f t1 t2 + = gApplyQ (gmapQ (\x -> GQ (f x)) t1) t2++gApplyQ :: Data a => [GQ r] -> a -> [r]+gApplyQ qs t = reverse (snd (gfoldlQ k z t))+ where+ k :: ([GQ r], [r]) -> GenericQ ([GQ r], [r])+ k (GQ q : qs, rs) child = (qs, q child : rs)+ z = (qs, [])++newtype R r x = R { unR :: r }++gfoldlQ :: (r -> GenericQ r)+ -> r + -> GenericQ r++gfoldlQ k z t = unR (gfoldl k' z' t)+ where+ z' _ = R z+ k' (R r) c = R (k r c)++-----------------------------------------------------------------------------++-- A dependently polymorphic geq+geq'' :: Data a => a -> a -> Bool+geq'' x y = toConstr x == toConstr y+ && and (gzipWithQ' geq'' x y)++-- A helper type for existentially quantified queries+data XQ r = forall a. Data a => XQ (a -> r)++-- A dependently polymorphic gzipWithQ+gzipWithQ' :: (forall a. Data a => a -> a -> r)+ -> (forall a. Data a => a -> a -> [r])+gzipWithQ' f t1 t2+ = gApplyQ' (gmapQ (\x -> XQ (f x)) t1) t2++-- Apply existentially quantified queries+-- Insist on equal types!+--+gApplyQ' :: Data a => [XQ r] -> a -> [r]+gApplyQ' qs t = reverse (snd (gfoldlQ k z t))+ where+ z = (qs, [])+ k :: ([XQ r], [r]) -> GenericQ ([XQ r], [r])+ k (XQ q : qs, rs) child = (qs, q' child : rs)+ where+ q' = error "Twin mismatch" `extQ` q+++-----------------------------------------------------------------------------++tests = ( geq [True,True] [True,True]+ , geq [True,True] [True,False]+ , geq'' [True,True] [True,True]+ , geq'' [True,True] [True,False]+ ) ~=? output++output = (True,False,True,False)
tests/Typecase1.hs view
@@ -1,59 +1,59 @@-{-# OPTIONS -fglasgow-exts #-} - -module Typecase1 (tests) where - -{- - -This test demonstrates type case as it lives in Data.Typeable. -We define a function f that converts typeables into strings in some way. -Note: we only need Data.Typeable. Say: Dynamics are NOT involved. - --} - -import Test.HUnit - -import Data.Typeable -import Data.Maybe - --- Some datatype. -data MyTypeable = MyCons String deriving (Show, Typeable) - --- --- Some function that performs type case. --- -f :: (Show a, Typeable a) => a -> String -f a = (maybe (maybe (maybe others - mytys (cast a) ) - float (cast a) ) - int (cast a) ) - - where - - -- do something with ints - int :: Int -> String - int a = "got an int, incremented: " ++ show (a + 1) - - -- do something with floats - float :: Float -> String - float a = "got a float, multiplied by .42: " ++ show (a * 0.42) - - -- do something with my typeables - mytys :: MyTypeable -> String - mytys a = "got a term: " ++ show a - - -- do something with all other typeables - others = "got something else: " ++ show a - - --- --- Test the type case --- -tests = ( f (41::Int) - , f (88::Float) - , f (MyCons "42") - , f True) ~=? output - -output = ( "got an int, incremented: 42" - , "got a float, multiplied by .42: 36.96" - , "got a term: MyCons \"42\"" +{-# OPTIONS -fglasgow-exts #-}++module Typecase1 (tests) where++{-++This test demonstrates type case as it lives in Data.Typeable.+We define a function f that converts typeables into strings in some way.+Note: we only need Data.Typeable. Say: Dynamics are NOT involved.++-}++import Test.HUnit++import Data.Typeable+import Data.Maybe++-- Some datatype.+data MyTypeable = MyCons String deriving (Show, Typeable)++--+-- Some function that performs type case.+--+f :: (Show a, Typeable a) => a -> String+f a = (maybe (maybe (maybe others+ mytys (cast a) )+ float (cast a) )+ int (cast a) )++ where++ -- do something with ints+ int :: Int -> String+ int a = "got an int, incremented: " ++ show (a + 1)++ -- do something with floats+ float :: Float -> String+ float a = "got a float, multiplied by .42: " ++ show (a * 0.42)++ -- do something with my typeables+ mytys :: MyTypeable -> String+ mytys a = "got a term: " ++ show a++ -- do something with all other typeables+ others = "got something else: " ++ show a+++--+-- Test the type case+--+tests = ( f (41::Int)+ , f (88::Float)+ , f (MyCons "42")+ , f True) ~=? output++output = ( "got an int, incremented: 42"+ , "got a float, multiplied by .42: 36.96"+ , "got a term: MyCons \"42\"" , "got something else: True")
tests/Typecase2.hs view
@@ -1,61 +1,61 @@-{-# OPTIONS -fglasgow-exts #-} - -module Typecase2 (tests) where - -{- - -This test provides a variation on typecase1.hs. -This time, we use generic show as defined for all instances of Data. -Thereby, we get rid of the Show constraint in our functions. -So we only keep a single constraint: the one for class Data. - --} - -import Test.HUnit - -import Data.Generics -import Data.Maybe - --- Some datatype. -data MyData = MyCons String deriving (Typeable, Data) - --- --- Some function that performs type case. --- -f :: Data a => a -> String -f a = (maybe (maybe (maybe others - mytys (cast a) ) - float (cast a) ) - int (cast a) ) - - where - - -- do something with ints - int :: Int -> String - int a = "got an int, incremented: " ++ show (a + 1) - - -- do something with floats - float :: Float -> String - float a = "got a float, multiplied by .42: " ++ show (a * 0.42) - - -- do something with my data - mytys :: MyData -> String - mytys a = "got my data: " ++ gshow a - - -- do something with all other data - others = "got something else: " ++ gshow a - - --- --- Test the type case --- -tests = ( f (41::Int) - , f (88::Float) - , f (MyCons "42") - , f True) ~=? output - -output = ( "got an int, incremented: 42" - , "got a float, multiplied by .42: 36.96" - , "got my data: (MyCons \"42\")" - , "got something else: (True)") - +{-# OPTIONS -fglasgow-exts #-}++module Typecase2 (tests) where++{-++This test provides a variation on typecase1.hs.+This time, we use generic show as defined for all instances of Data.+Thereby, we get rid of the Show constraint in our functions.+So we only keep a single constraint: the one for class Data.++-}++import Test.HUnit++import Data.Generics+import Data.Maybe++-- Some datatype.+data MyData = MyCons String deriving (Typeable, Data)++--+-- Some function that performs type case.+--+f :: Data a => a -> String+f a = (maybe (maybe (maybe others+ mytys (cast a) )+ float (cast a) )+ int (cast a) )++ where++ -- do something with ints+ int :: Int -> String+ int a = "got an int, incremented: " ++ show (a + 1)++ -- do something with floats+ float :: Float -> String+ float a = "got a float, multiplied by .42: " ++ show (a * 0.42)++ -- do something with my data+ mytys :: MyData -> String+ mytys a = "got my data: " ++ gshow a++ -- do something with all other data+ others = "got something else: " ++ gshow a+++--+-- Test the type case+--+tests = ( f (41::Int)+ , f (88::Float)+ , f (MyCons "42")+ , f True) ~=? output++output = ( "got an int, incremented: 42"+ , "got a float, multiplied by .42: 36.96"+ , "got my data: (MyCons \"42\")"+ , "got something else: (True)")+
tests/Where.hs view
@@ -1,125 +1,125 @@-{-# OPTIONS -fglasgow-exts #-} - -module Where (tests) where - -{- - -This example illustrates some differences between certain traversal -schemes. To this end, we use a simple system of datatypes, and the -running example shall be to replace "T1a 42" by "T1a 88". It is our -intention to illustrate a few dimensions of designing traversals. - -1. We can decide on whether we prefer "rewrite steps" (i.e., -monomorphic functions on data) that succeed either for all input -patterns or only if the encounter a term pattern to be replaced. In -the first case, the catch-all equation of such a function describes -identity (see "stepid" below). In the second case, the catch-call -equation describes failure using the Maybe type constructor (see -"stepfail" below). As an intermediate assessment, the failure approach -is more general because it allows one to observe if a rewrite step was -meaningful or not. Often the identity approach is more convenient and -sufficient. - -2. We can now also decide on whether we want monadic or simple -traversals; recall monadic generic functions GenericM from -Data.Generics. The monad can serve for success/failure, state, -environment and others. One can now subdivide monadic traversal -schemes with respect to the question whether they simply support -monadic style of whether they even interact with the relevant -monad. The scheme "everywereM" from the library belongs to the first -category while "somewhere" belongs to the second category as it uses -the operation "mplus" of a monad with addition. So while "everywhereM" -makes very well sense without a monad --- as demonstrated by -"everywhere", the scheme "somewhere" is immediately monadic. - -3. We can now also decide on whether we want rewrite steps to succeed -for all possible subterms, at least for one subterm, exactly for one -subterm, and others. The various traversal schemes make different -assumptions in this respect. - -a) everywhere - - By its type, succeeds and requires non-failing rewrite steps. - However, we do not get any feedback on whether terms were actually - rewritten. (Say, we might have performed accidentally the identity - function on all nodes.) - -b) everywhereM - - Attempts to reach all nodes where all the sub-traversals are performed - in monadic bind-sequence. Failure of the traversal for a given subterm - implies failure of the entire traversal. Hence, the argument of - "everywhereM" should be designed in a way that it tends to succeed - except for the purpose of propagating a proper error in the sense of - violating a pre-/post-condition. For example, "mkM stepfail" should - not be passed to "everywhereM" as it will fail for all but one term - pattern; see "recovered" for a way to massage "stepfail" accordingly. - -c) somewhere - - Descends into term in a top-down manner, and stops in a given - branch when the argument succeeds for the subterm at hand. To this - end, it takes an argument that is perfectly intended to fail for - certain term patterns. Thanks to the employment of gmapF, the - traversal scheme recovers from failure when mapping over the immediate - subterms while insisting success for at least one subterm (say, branch). - This scheme is appropriate if you want to make sure that a given - rewrite step was actually used in a traversal. So failure of the - traversal would mean that the argument failed for all subterms. - -Contributed by Ralf Laemmel, ralf@cwi.nl - --} - -import Test.HUnit - -import Data.Generics -import Control.Monad - - --- Two mutually recursive datatypes -data T1 = T1a Int | T1b T2 deriving (Typeable, Data) -data T2 = T2 T1 deriving (Typeable, Data) - - --- A rewrite step with identity as catch-all case -stepid (T1a 42) = T1a 88 -stepid x = x - - --- The same rewrite step but now with failure as catch-all case -stepfail (T1a 42) = Just (T1a 88) -stepfail _ = Nothing - - --- We can let recover potentially failing generic functions from failure; --- this is illustrated for a generic made from stepfail via mkM. -recovered x = mkM stepfail x `mplus` Just x - - --- A test term that comprehends a redex -term42 = T1b (T2 (T1a 42)) - - --- A test term that does not comprehend a redex -term37 = T1b (T2 (T1a 37)) - - --- A number of traversals -result1 = everywhere (mkT stepid) term42 -- rewrites term accordingly -result2 = everywhere (mkT stepid) term37 -- preserves term without notice -result3 = everywhereM (mkM stepfail) term42 -- fails in a harsh manner -result4 = everywhereM (mkM stepfail) term37 -- fails rather early -result5 = everywhereM recovered term37 -- preserves term without notice -result6 = somewhere (mkMp stepfail) term42 -- rewrites term accordingly -result7 = somewhere (mkMp stepfail) term37 -- fails to notice lack of redex - -tests = gshow ( result1, - ( result2, - ( result3, - ( result4, - ( result5, - ( result6, - ( result7 ))))))) ~=? output - -output = "((,) (T1b (T2 (T1a (88)))) ((,) (T1b (T2 (T1a (37)))) ((,) (Nothing) ((,) (Nothing) ((,) (Just (T1b (T2 (T1a (37))))) ((,) (Just (T1b (T2 (T1a (88))))) (Nothing)))))))" +{-# OPTIONS -fglasgow-exts #-}++module Where (tests) where++{-++This example illustrates some differences between certain traversal+schemes. To this end, we use a simple system of datatypes, and the+running example shall be to replace "T1a 42" by "T1a 88". It is our+intention to illustrate a few dimensions of designing traversals.++1. We can decide on whether we prefer "rewrite steps" (i.e.,+monomorphic functions on data) that succeed either for all input+patterns or only if the encounter a term pattern to be replaced. In+the first case, the catch-all equation of such a function describes+identity (see "stepid" below). In the second case, the catch-call+equation describes failure using the Maybe type constructor (see+"stepfail" below). As an intermediate assessment, the failure approach+is more general because it allows one to observe if a rewrite step was+meaningful or not. Often the identity approach is more convenient and+sufficient.++2. We can now also decide on whether we want monadic or simple+traversals; recall monadic generic functions GenericM from+Data.Generics. The monad can serve for success/failure, state,+environment and others. One can now subdivide monadic traversal+schemes with respect to the question whether they simply support+monadic style of whether they even interact with the relevant+monad. The scheme "everywereM" from the library belongs to the first+category while "somewhere" belongs to the second category as it uses+the operation "mplus" of a monad with addition. So while "everywhereM"+makes very well sense without a monad --- as demonstrated by+"everywhere", the scheme "somewhere" is immediately monadic.++3. We can now also decide on whether we want rewrite steps to succeed+for all possible subterms, at least for one subterm, exactly for one+subterm, and others. The various traversal schemes make different+assumptions in this respect.++a) everywhere++ By its type, succeeds and requires non-failing rewrite steps.+ However, we do not get any feedback on whether terms were actually+ rewritten. (Say, we might have performed accidentally the identity+ function on all nodes.)++b) everywhereM++ Attempts to reach all nodes where all the sub-traversals are performed+ in monadic bind-sequence. Failure of the traversal for a given subterm+ implies failure of the entire traversal. Hence, the argument of + "everywhereM" should be designed in a way that it tends to succeed+ except for the purpose of propagating a proper error in the sense of+ violating a pre-/post-condition. For example, "mkM stepfail" should+ not be passed to "everywhereM" as it will fail for all but one term + pattern; see "recovered" for a way to massage "stepfail" accordingly.++c) somewhere++ Descends into term in a top-down manner, and stops in a given+ branch when the argument succeeds for the subterm at hand. To this+ end, it takes an argument that is perfectly intended to fail for+ certain term patterns. Thanks to the employment of gmapF, the+ traversal scheme recovers from failure when mapping over the immediate+ subterms while insisting success for at least one subterm (say, branch).+ This scheme is appropriate if you want to make sure that a given+ rewrite step was actually used in a traversal. So failure of the+ traversal would mean that the argument failed for all subterms.++Contributed by Ralf Laemmel, ralf@cwi.nl++-}++import Test.HUnit++import Data.Generics+import Control.Monad+++-- Two mutually recursive datatypes+data T1 = T1a Int | T1b T2 deriving (Typeable, Data)+data T2 = T2 T1 deriving (Typeable, Data)+++-- A rewrite step with identity as catch-all case+stepid (T1a 42) = T1a 88+stepid x = x+++-- The same rewrite step but now with failure as catch-all case+stepfail (T1a 42) = Just (T1a 88)+stepfail _ = Nothing+++-- We can let recover potentially failing generic functions from failure;+-- this is illustrated for a generic made from stepfail via mkM.+recovered x = mkM stepfail x `mplus` Just x+++-- A test term that comprehends a redex+term42 = T1b (T2 (T1a 42))+++-- A test term that does not comprehend a redex+term37 = T1b (T2 (T1a 37))+++-- A number of traversals+result1 = everywhere (mkT stepid) term42 -- rewrites term accordingly+result2 = everywhere (mkT stepid) term37 -- preserves term without notice+result3 = everywhereM (mkM stepfail) term42 -- fails in a harsh manner+result4 = everywhereM (mkM stepfail) term37 -- fails rather early+result5 = everywhereM recovered term37 -- preserves term without notice+result6 = somewhere (mkMp stepfail) term42 -- rewrites term accordingly+result7 = somewhere (mkMp stepfail) term37 -- fails to notice lack of redex++tests = gshow ( result1,+ ( result2,+ ( result3,+ ( result4,+ ( result5,+ ( result6,+ ( result7 ))))))) ~=? output++output = "((,) (T1b (T2 (T1a (88)))) ((,) (T1b (T2 (T1a (37)))) ((,) (Nothing) ((,) (Nothing) ((,) (Just (T1b (T2 (T1a (37))))) ((,) (Just (T1b (T2 (T1a (88))))) (Nothing)))))))"
tests/XML.hs view
@@ -1,207 +1,207 @@-{-# OPTIONS -fglasgow-exts #-} - -module XML (tests) where - -{- - -This example illustrates XMLish services -to trealise (say, "serialise") heterogenous -Haskell data as homogeneous tree structures -(say, XMLish elements) and vice versa. - --} - -import Test.HUnit - -import Control.Applicative (Alternative(..), Applicative(..)) -import Control.Monad -import Data.Maybe -import Data.Generics -import CompanyDatatypes - - --- HaXml-like types for XML elements -data Element = Elem Name [Attribute] [Content] - deriving (Show, Eq, Typeable, Data) - -data Content = CElem Element - | CString Bool CharData - -- ^ bool is whether whitespace is significant - | CRef Reference - | CMisc Misc - deriving (Show, Eq, Typeable, Data) - -type CharData = String - - --- In this simple example we disable some parts of XML -type Attribute = () -type Reference = () -type Misc = () - - --- Trealisation -data2content :: Data a => a -> [Content] -data2content = element - `ext1Q` list - `extQ` string - `extQ` float - - where - - -- Handle an element - element x = [CElem (Elem (tyconUQname (dataTypeName (dataTypeOf x))) - [] -- no attributes - (concat (gmapQ data2content x)))] - - -- A special case for lists - list :: Data a => [a] -> [Content] - list = concat . map data2content - - -- A special case for strings - string :: String -> [Content] - string x = [CString True x] - - -- A special case for floats - float :: Float -> [Content] - float x = [CString True (show x)] - - --- De-trealisation -content2data :: forall a. Data a => ReadX a -content2data = result - - where - - -- Case-discriminating worker - result = element - `ext1R` list - `extR` string - `extR` float - - - -- Determine type of data to be constructed - myType = myTypeOf result - where - myTypeOf :: forall a. ReadX a -> a - myTypeOf = undefined - - -- Handle an element - element = do c <- readX - case c of - (CElem (Elem x as cs)) - | as == [] -- no attributes - && x == (tyconUQname (dataTypeName (dataTypeOf myType))) - -> alts cs - _ -> mzero - - - -- A special case for lists - list :: forall a. Data a => ReadX [a] - list = ( do h <- content2data - t <- list - return (h:t) ) - `mplus` return [] - - -- Fold over all alternatives, say constructors - alts cs = foldr (mplus . recurse cs) mzero shapes - - -- Possible top-level shapes - shapes = map fromConstr consOf - - -- Retrieve all constructors of the requested type - consOf = dataTypeConstrs - $ dataTypeOf - $ myType - - -- Recurse into subterms - recurse cs x = maybe mzero - return - (runReadX (gmapM (const content2data) x) cs) - - -- A special case for strings - string :: ReadX String - string = do c <- readX - case c of - (CString _ x) -> return x - _ -> mzero - - -- A special case for floats - float :: ReadX Float - float = do c <- readX - case c of - (CString _ x) -> return (read x) - _ -> mzero - - - ------------------------------------------------------------------------------ --- --- An XML-hungry parser-like monad --- ------------------------------------------------------------------------------ - --- Type constructor -newtype ReadX a = - ReadX { unReadX :: [Content] - -> Maybe ([Content], a) } - --- Run a computation -runReadX x y = case unReadX x y of - Just ([],y) -> Just y - _ -> Nothing - --- Read one content particle -readX :: ReadX Content -readX = ReadX (\x -> if null x - then Nothing - else Just (tail x, head x) - ) - -instance Functor ReadX where - fmap = liftM - -instance Applicative ReadX where - pure = return - (<*>) = ap - -instance Alternative ReadX where - (<|>) = mplus - empty = mzero - --- ReadX is a monad! -instance Monad ReadX where - return x = ReadX (\y -> Just (y,x)) - c >>= f = ReadX (\x -> case unReadX c x of - Nothing -> Nothing - Just (x', a) -> unReadX (f a) x' - ) - --- ReadX also accommodates mzero and mplus! -instance MonadPlus ReadX where - mzero = ReadX (const Nothing) - f `mplus` g = ReadX (\x -> case unReadX f x of - Nothing -> unReadX g x - y -> y - ) - - - ------------------------------------------------------------------------------ --- --- Main function for testing --- ------------------------------------------------------------------------------ - -tests = ( genCom - , ( data2content genCom - , ( zigzag person1 :: Maybe Person - , ( zigzag genCom :: Maybe Company - , ( zigzag genCom == Just genCom - ))))) ~=? output - where - -- Trealise back and forth - zigzag :: Data a => a -> Maybe a - zigzag = runReadX content2data . data2content - -output = (C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8000.0)) [PU (E (P "Joost" "Amsterdam") (S 1000.0)),PU (E (P "Marlow" "Cambridge") (S 2000.0))],D "Strategy" (E (P "Blair" "London") (S 100000.0)) []],([CElem (Elem "Company" [] [CElem (Elem "Dept" [] [CString True "Research",CElem (Elem "Employee" [] [CElem (Elem "Person" [] [CString True "Laemmel",CString True "Amsterdam"]),CElem (Elem "Salary" [] [CString True "8000.0"])]),CElem (Elem "Unit" [] [CElem (Elem "Employee" [] [CElem (Elem "Person" [] [CString True "Joost",CString True "Amsterdam"]),CElem (Elem "Salary" [] [CString True "1000.0"])])]),CElem (Elem "Unit" [] [CElem (Elem "Employee" [] [CElem (Elem "Person" [] [CString True "Marlow",CString True "Cambridge"]),CElem (Elem "Salary" [] [CString True "2000.0"])])])]),CElem (Elem "Dept" [] [CString True "Strategy",CElem (Elem "Employee" [] [CElem (Elem "Person" [] [CString True "Blair",CString True "London"]),CElem (Elem "Salary" [] [CString True "100000.0"])])])])],(Just (P "Lazy" "Home"),(Just (C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8000.0)) [PU (E (P "Joost" "Amsterdam") (S 1000.0)),PU (E (P "Marlow" "Cambridge") (S 2000.0))],D "Strategy" (E (P "Blair" "London") (S 100000.0)) []]),True)))) +{-# OPTIONS -fglasgow-exts #-}++module XML (tests) where++{-++This example illustrates XMLish services+to trealise (say, "serialise") heterogenous+Haskell data as homogeneous tree structures+(say, XMLish elements) and vice versa.++-}++import Test.HUnit++import Control.Applicative (Alternative(..), Applicative(..))+import Control.Monad+import Data.Maybe+import Data.Generics+import CompanyDatatypes+++-- HaXml-like types for XML elements+data Element = Elem Name [Attribute] [Content]+ deriving (Show, Eq, Typeable, Data)++data Content = CElem Element+ | CString Bool CharData+ -- ^ bool is whether whitespace is significant+ | CRef Reference+ | CMisc Misc+ deriving (Show, Eq, Typeable, Data)++type CharData = String+++-- In this simple example we disable some parts of XML+type Attribute = ()+type Reference = ()+type Misc = ()+++-- Trealisation+data2content :: Data a => a -> [Content]+data2content = element+ `ext1Q` list+ `extQ` string + `extQ` float++ where++ -- Handle an element+ element x = [CElem (Elem (tyconUQname (dataTypeName (dataTypeOf x)))+ [] -- no attributes + (concat (gmapQ data2content x)))]++ -- A special case for lists+ list :: Data a => [a] -> [Content]+ list = concat . map data2content++ -- A special case for strings+ string :: String -> [Content]+ string x = [CString True x]++ -- A special case for floats+ float :: Float -> [Content]+ float x = [CString True (show x)]+++-- De-trealisation+content2data :: forall a. Data a => ReadX a+content2data = result++ where+ + -- Case-discriminating worker+ result = element+ `ext1R` list+ `extR` string+ `extR` float+++ -- Determine type of data to be constructed+ myType = myTypeOf result+ where+ myTypeOf :: forall a. ReadX a -> a+ myTypeOf = undefined++ -- Handle an element+ element = do c <- readX+ case c of+ (CElem (Elem x as cs))+ | as == [] -- no attributes+ && x == (tyconUQname (dataTypeName (dataTypeOf myType)))+ -> alts cs+ _ -> mzero+++ -- A special case for lists+ list :: forall a. Data a => ReadX [a]+ list = ( do h <- content2data+ t <- list+ return (h:t) )+ `mplus` return []++ -- Fold over all alternatives, say constructors+ alts cs = foldr (mplus . recurse cs) mzero shapes++ -- Possible top-level shapes+ shapes = map fromConstr consOf++ -- Retrieve all constructors of the requested type+ consOf = dataTypeConstrs+ $ dataTypeOf + $ myType++ -- Recurse into subterms+ recurse cs x = maybe mzero+ return+ (runReadX (gmapM (const content2data) x) cs)++ -- A special case for strings+ string :: ReadX String+ string = do c <- readX+ case c of+ (CString _ x) -> return x+ _ -> mzero++ -- A special case for floats+ float :: ReadX Float+ float = do c <- readX+ case c of+ (CString _ x) -> return (read x)+ _ -> mzero++++-----------------------------------------------------------------------------+--+-- An XML-hungry parser-like monad+--+-----------------------------------------------------------------------------++-- Type constructor+newtype ReadX a =+ ReadX { unReadX :: [Content]+ -> Maybe ([Content], a) }++-- Run a computation+runReadX x y = case unReadX x y of + Just ([],y) -> Just y+ _ -> Nothing++-- Read one content particle+readX :: ReadX Content+readX = ReadX (\x -> if null x + then Nothing+ else Just (tail x, head x)+ )++instance Functor ReadX where+ fmap = liftM++instance Applicative ReadX where+ pure = return+ (<*>) = ap++instance Alternative ReadX where+ (<|>) = mplus+ empty = mzero++-- ReadX is a monad!+instance Monad ReadX where+ return x = ReadX (\y -> Just (y,x))+ c >>= f = ReadX (\x -> case unReadX c x of+ Nothing -> Nothing+ Just (x', a) -> unReadX (f a) x'+ )++-- ReadX also accommodates mzero and mplus!+instance MonadPlus ReadX where+ mzero = ReadX (const Nothing)+ f `mplus` g = ReadX (\x -> case unReadX f x of+ Nothing -> unReadX g x+ y -> y+ )++++-----------------------------------------------------------------------------+--+-- Main function for testing+--+-----------------------------------------------------------------------------++tests = ( genCom+ , ( data2content genCom+ , ( zigzag person1 :: Maybe Person+ , ( zigzag genCom :: Maybe Company+ , ( zigzag genCom == Just genCom+ ))))) ~=? output+ where + -- Trealise back and forth+ zigzag :: Data a => a -> Maybe a+ zigzag = runReadX content2data . data2content++output = (C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8000.0)) [PU (E (P "Joost" "Amsterdam") (S 1000.0)),PU (E (P "Marlow" "Cambridge") (S 2000.0))],D "Strategy" (E (P "Blair" "London") (S 100000.0)) []],([CElem (Elem "Company" [] [CElem (Elem "Dept" [] [CString True "Research",CElem (Elem "Employee" [] [CElem (Elem "Person" [] [CString True "Laemmel",CString True "Amsterdam"]),CElem (Elem "Salary" [] [CString True "8000.0"])]),CElem (Elem "Unit" [] [CElem (Elem "Employee" [] [CElem (Elem "Person" [] [CString True "Joost",CString True "Amsterdam"]),CElem (Elem "Salary" [] [CString True "1000.0"])])]),CElem (Elem "Unit" [] [CElem (Elem "Employee" [] [CElem (Elem "Person" [] [CString True "Marlow",CString True "Cambridge"]),CElem (Elem "Salary" [] [CString True "2000.0"])])])]),CElem (Elem "Dept" [] [CString True "Strategy",CElem (Elem "Employee" [] [CElem (Elem "Person" [] [CString True "Blair",CString True "London"]),CElem (Elem "Salary" [] [CString True "100000.0"])])])])],(Just (P "Lazy" "Home"),(Just (C [D "Research" (E (P "Laemmel" "Amsterdam") (S 8000.0)) [PU (E (P "Joost" "Amsterdam") (S 1000.0)),PU (E (P "Marlow" "Cambridge") (S 2000.0))],D "Strategy" (E (P "Blair" "London") (S 100000.0)) []]),True))))