transformers-bifunctors (empty) → 0.1

raw patch · 6 files changed

+217/−0 lines, 6 filesdep +basedep +mmorphdep +transformerssetup-changed

Dependencies added: base, mmorph, transformers

Files

• CHANGELOG.md +3/−0
• LICENSE +30/−0
• README.md +9/−0
• Setup.hs +2/−0
• src/Control/Monad/Trans/Bifunctor.hs +128/−0
• transformers-bifunctors.cabal +45/−0

@@ -0,0 +1,3 @@+## Version 0.1 (2017-07-16)++* First version. Released on an unsuspecting world.

@@ -0,0 +1,30 @@+Copyright (c) 2017, Jacob Stanley++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 the name of Jacob Stanley nor the names of other+      contributors may be used to endorse or promote products derived+      from this software without specific prior written permission.++THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 COPYRIGHT+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

@@ -0,0 +1,9 @@+transformers-bifunctors [![Hackage][hackage-shield]][hackage]+=======================++Bifunctors over monad transformers.++[hackage]:+  http://hackage.haskell.org/package/transformers-bifunctors+[hackage-shield]:+  https://img.shields.io/hackage/v/transformers-bifunctors.svg

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

@@ -0,0 +1,128 @@+{-# LANGUAGE LambdaCase #-}+module Control.Monad.Trans.Bifunctor (+    BifunctorTrans(..)+  , bimapX+  , firstX+  , secondX+  ) where++import           Control.Monad.Morph (MMonad, squash, hoist)+import           Control.Monad.Trans.Except (ExceptT(..), runExceptT)+import qualified Control.Monad.Trans.Writer.Lazy as Lazy+import qualified Control.Monad.Trans.Writer.Strict as Strict+++-- | Class of monad transformers which are bifunctors.+--+--   You can implement a 'BifunctorTrans' by either defining 'bimapT' or by+--   defining both 'firstT' and 'secondT'.+--+--   If you supply 'bimapT', you should ensure that:+--+-- @'bimapT' 'id' 'id' ≡ 'id'@+--+--   If you supply 'first' and 'second', ensure:+--+-- @+-- 'firstT'  'id' ≡ 'id'+-- 'secondT' 'id' ≡ 'id'+-- @+--+--   If you supply both, you should also ensure:+--+-- @'bimapT' f g ≡ 'firstT' f '.' 'secondT' g@+--+--   These ensure by parametricity:+--+-- @+-- 'bimapT'  (f '.' g) (h '.' i) ≡ 'bimapT' f h '.' 'bimapT' g i+-- 'firstT'  (f '.' g) ≡ 'firstT'  f '.' 'firstT'  g+-- 'secondT' (f '.' g) ≡ 'secondT' f '.' 'secondT' g+-- @+--+class BifunctorTrans t where+  {-# MINIMAL bimapT | firstT, secondT #-}++  -- | Map over both arguments at the same time.+  --+  -- @'bimap' f g ≡ 'first' f '.' 'second' g@+  --+  bimapT :: Functor f => (x -> y) -> (a -> b) -> t x f a -> t y f b+  bimapT f g =+    firstT f . secondT g+  {-# INLINE bimapT #-}++  -- | Map covariantly over the first argument.+  --+  -- @'firstT' f ≡ 'bimapT' f 'id'@+  --+  firstT :: Functor f => (x -> y) -> t x f a -> t y f a+  firstT f =+    bimapT f id+  {-# INLINE firstT #-}++  -- | Map covariantly over the second argument.+  --+  -- @'second' ≡ 'bimap' 'id'@+  --+  secondT :: Functor f => (a -> b) -> t x f a -> t x f b+  secondT =+    bimapT id+  {-# INLINE secondT #-}++instance BifunctorTrans ExceptT where+  bimapT f g =+    let+      h = \case+        Left x ->+          Left (f x)+        Right a ->+          Right (g a)+      {-# INLINE h #-}+    in+      ExceptT . fmap h . runExceptT+  {-# INLINE bimapT #-}++instance BifunctorTrans Lazy.WriterT where+  bimapT f g =+    let+      h (a, x) =+        (g a, f x)+      {-# INLINE h #-}+    in+      Lazy.WriterT . fmap h . Lazy.runWriterT+  {-# INLINE bimapT #-}++instance BifunctorTrans Strict.WriterT where+  bimapT f g =+    let+      h (a, x) =+        (g a, f x)+      {-# INLINE h #-}+    in+      Strict.WriterT . fmap h . Strict.runWriterT+  {-# INLINE bimapT #-}++-- | Map over two stacked transformer bifunctors, unifying their type and+--   squashing the result.+--+bimapX :: (BifunctorTrans t, MMonad (t z), Monad (t y m), Monad m) => (x -> z) -> (y -> z) -> t x (t y m) a -> t z m a+bimapX f g =+  squash . hoist (firstT g) . firstT f+{-# INLINE bimapX #-}++-- | Map over the first of two stacked transformer bifunctors, unifying their+--   type and squashing the result.+--+firstX :: (BifunctorTrans t, MMonad (t y), Functor (t y m), Monad m) => (x -> y) -> t x (t y m) a -> t y m a+firstX f =+  squash . firstT f+{-# INLINE firstX #-}++-- | Map over the second of two stacked transformer bifunctors, unifying their+--   type and squashing the result.+--+secondX :: (BifunctorTrans t, MMonad (t x), Monad (t y m), Monad m) => (y -> x) -> t x (t y m) a -> t x m a+secondX f =+  squash . hoist (firstT f)+{-# INLINE secondX #-}

@@ -0,0 +1,45 @@+version: 0.1++name:+  transformers-bifunctors+author:+  Jacob Stanley+maintainer:+  Jacob Stanley <jacob@stanley.io>+homepage:+  https://github.com/jystic/transformers-bifunctors+bug-reports:+  https://github.com/jystic/transformers-bifunctors/issues+synopsis:+  Bifunctors over monad transformers.+description:+  Bifunctors over monad transformers.+category:+  Control, Functors+license:+  BSD3+license-file:+  LICENSE+cabal-version:+  >= 1.8+build-type:+  Simple+extra-source-files:+  README.md+  CHANGELOG.md++source-repository head+  type: git+  location: git://github.com/jystic/transformers-bifunctors.git++library+  build-depends:+      base                            >= 3          && < 5+    , mmorph                          >= 1.0        && < 1.2+    , transformers                    >= 0.3        && < 0.6++  hs-source-dirs:+    src++  exposed-modules:     +    Control.Monad.Trans.Bifunctor