profunctors 4.0.2 → 4.0.3

raw patch · 4 files changed

+67/−3 lines, 4 files

Files

• CHANGELOG.markdown +4/−0
• profunctors.cabal +2/−1
• src/Data/Profunctor/Lift.hs +59/−0
• src/Data/Profunctor/Rift.hs +2/−2

@@ -1,3 +1,7 @@+4.0.3+-----+* Added `Data.Profunctor.Lift` containing the left Kan lift of a profunctor.+ 4.0.2 ----- * Added `assoc` to `Data.Profunctor.Composition` so that we have all 3 associators.

@@ -1,6 +1,6 @@ name:          profunctors category:      Control, Categories-version:       4.0.2+version:       4.0.3 license:       BSD3 cabal-version: >= 1.10 license-file:  LICENSE@@ -37,6 +37,7 @@     Data.Profunctor     Data.Profunctor.Composition     Data.Profunctor.Collage+    Data.Profunctor.Lift     Data.Profunctor.Rep     Data.Profunctor.Rift     Data.Profunctor.Trace

@@ -0,0 +1,59 @@+{-# LANGUAGE CPP #-}+{-# LANGUAGE Rank2Types #-}+{-# LANGUAGE TypeFamilies #-}+#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 702+{-# LANGUAGE Trustworthy #-}+#endif+-----------------------------------------------------------------------------+-- |+-- Copyright   :  (C) 2014 Edward Kmett+-- License     :  BSD-style (see the file LICENSE)+--+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>+-- Stability   :  provisional+-- Portability :  Rank2Types, TFs+--+----------------------------------------------------------------------------+module Data.Profunctor.Lift+  ( Lift(..)+  , decomposeLift+  ) where++import Control.Category+import Data.Profunctor.Unsafe+import Data.Profunctor.Composition+import Prelude hiding (id,(.))++-- | This represents the left Kan lift of a 'Profunctor' @q@ along a 'Profunctor' @p@ in a limited version of the 2-category of Profunctors where the only object is the category Hask, 1-morphisms are profunctors composed and compose with Profunctor composition, and 2-morphisms are just natural transformations.+newtype Lift p q a b = Lift { runLift :: forall x. p b x -> q a x }+++instance (Profunctor p, Profunctor q) => Profunctor (Lift p q) where+  dimap ca bd f = Lift (lmap ca . runLift f . lmap bd)+  {-# INLINE dimap #-}+  lmap ca f = Lift (lmap ca . runLift f)+  {-# INLINE lmap #-}+  rmap bd f = Lift (runLift f . lmap bd)+  {-# INLINE rmap #-}+  bd #. f = Lift (\p -> runLift f (p .# bd))+  {-# INLINE ( #. ) #-}+  f .# ca = Lift (\p -> runLift f p .# ca)+  {-# INLINE (.#) #-}++instance Profunctor p => Functor (Lift p q a) where+  fmap bd f = Lift (runLift f . lmap bd)+  {-# INLINE fmap #-}++-- | @'Lift' p p@ forms a 'Monad' in the 'Profunctor' 2-category, which is isomorphic to a Haskell 'Category' instance.+instance p ~ q => Category (Lift p q) where+  id = Lift id+  {-# INLINE id #-}+  Lift f . Lift g = Lift (g . f)+  {-# INLINE (.) #-}++-- | The 2-morphism that defines a left Kan lift.+--+-- Note: When @p@ is right adjoint to @'Lift' p (->)@ then 'decomposeLift' is the 'counit' of the adjunction.+decomposeLift :: Procompose (Lift p q) p a b -> q a b+decomposeLift (Procompose (Lift pq) p) = pq p+{-# INLINE decomposeLift #-}

@@ -11,7 +11,7 @@ -- -- Maintainer  :  Edward Kmett <ekmett@gmail.com> -- Stability   :  provisional--- Portability :  Rank2Types+-- Portability :  Rank2Types, TFs -- ---------------------------------------------------------------------------- module Data.Profunctor.Rift@@ -55,7 +55,7 @@  -- | The 2-morphism that defines a right Kan lift. ----- Note: When @f@ is left adjoint to @'Rift' f (->)@ then 'decomposeRift' is the 'counit' of the adjunction.+-- Note: When @q@ is left adjoint to @'Rift' q (->)@ then 'decomposeRift' is the 'counit' of the adjunction. decomposeRift :: Procompose q (Rift q p) a b -> p a b decomposeRift (Procompose q (Rift qp)) = qp q {-# INLINE decomposeRift #-}