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moved Biapply from semigroupoids to reduce dependencies

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commit 340d4ba3d987b960bbdbd496f53d1c77096c7226 1 parent 849225f
@ekmett authored
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1  Data/Bifoldable.hs
@@ -18,6 +18,7 @@ module Data.Bifoldable
, bitraverse_
, bifor_
, bimapM_
+ , biforM_
, bisequenceA_
, bisequence_
, biList
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62 Data/Bifunctor/Apply.hs
@@ -0,0 +1,62 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module : Data.Bifunctor.Apply
+-- Copyright : (C) 2011 Edward Kmett,
+-- License : BSD-style (see the file LICENSE)
+--
+-- Maintainer : Edward Kmett <ekmett@gmail.com>
+-- Stability : provisional
+-- Portability : portable
+--
+----------------------------------------------------------------------------
+module Data.Bifunctor.Apply (
+ -- * Functors
+ -- * Applyable bifunctors
+ Biapply(..)
+ , (<<$>>)
+ , (<<..>>)
+ , bilift2
+ , bilift3
+ , module Data.Bifunctor
+ ) where
+
+-- import _everything_
+import Data.Bifunctor
+
+infixl 4 <<$>>, <<.>>, <<., .>>, <<..>>
+
+(<<$>>) :: (a -> b) -> a -> b
+(<<$>>) = id
+
+-- | A strong lax semi-monoidal endofunctor.
+-- This is equivalent to an 'Applicative' without 'pure'.
+--
+-- Laws:
+--
+-- > associative composition: (.) <$> u <.> v <.> w = u <.> (v <.> w)
+class Bifunctor p => Biapply p where
+ (<<.>>) :: p (a -> b) (c -> d) -> p a c -> p b d
+
+ -- | a .> b = const id <$> a <.> b
+ (.>>) :: p a b -> p c d -> p c d
+ a .>> b = bimap (const id) (const id) <<$>> a <<.>> b
+
+ -- | a <. b = const <$> a <.> b
+ (<<.) :: p a b -> p c d -> p a b
+ a <<. b = bimap const const <<$>> a <<.>> b
+
+(<<..>>) :: Biapply p => p a c -> p (a -> b) (c -> d) -> p b d
+(<<..>>) = bilift2 (flip id) (flip id)
+
+-- | Lift a binary function into a comonad with zipping
+bilift2 :: Biapply w => (a -> b -> c) -> (d -> e -> f) -> w a d -> w b e -> w c f
+bilift2 f g a b = bimap f g <<$>> a <<.>> b
+{-# INLINE bilift2 #-}
+
+-- | Lift a ternary function into a comonad with zipping
+bilift3 :: Biapply w => (a -> b -> c -> d) -> (e -> f -> g -> h) -> w a e -> w b f -> w c g -> w d h
+bilift3 f g a b c = bimap f g <<$>> a <<.>> b <<.>> c
+{-# INLINE bilift3 #-}
+
+instance Biapply (,) where
+ (f, g) <<.>> (a, b) = (f a, g b)
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3  bifunctors.cabal
@@ -1,6 +1,6 @@
name: bifunctors
category: Data, Functors
-version: 0.1
+version: 0.1.1
license: BSD3
cabal-version: >= 1.6
license-file: LICENSE
@@ -23,6 +23,7 @@ library
exposed-modules:
Data.Bifunctor
+ Data.Bifunctor.Apply
Data.Bifoldable
Data.Bitraversable
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