{-# LANGUAGE CPP #-} #ifdef TRUSTWORTHY {-# LANGUAGE Trustworthy #-} #endif ----------------------------------------------------------------------------- -- | -- Module : Control.Lens.Internal.Iso -- Copyright : (C) 2012-2014 Edward Kmett -- License : BSD-style (see the file LICENSE) -- Maintainer : Edward Kmett <ekmett@gmail.com> -- Stability : experimental -- Portability : non-portable -- ---------------------------------------------------------------------------- module Control.Lens.Internal.Iso ( Exchange(..) , Reversing(..) ) where import Data.Profunctor #ifndef SAFE import Data.Profunctor.Unsafe import Unsafe.Coerce #endif import Data.ByteString as StrictB import Data.ByteString.Lazy as LazyB import Data.Text as StrictT import Data.Text.Lazy as LazyT import Data.Vector as Vector import Data.Vector.Primitive as Prim import Data.Vector.Storable as Storable import Data.Vector.Unboxed as Unbox import Data.Sequence as Seq ------------------------------------------------------------------------------ -- Isomorphism: Exchange ------------------------------------------------------------------------------ -- | This is used internally by the 'Control.Lens.Iso.Iso' code to provide -- efficient access to the two functions that make up an isomorphism. data Exchange a b s t = Exchange (s -> a) (b -> t) instance Functor (Exchange a b s) where fmap f (Exchange sa bt) = Exchange sa (f . bt) {-# INLINE fmap #-} instance Profunctor (Exchange a b) where dimap f g (Exchange sa bt) = Exchange (sa . f) (g . bt) {-# INLINE dimap #-} lmap f (Exchange sa bt) = Exchange (sa . f) bt {-# INLINE lmap #-} rmap f (Exchange sa bt) = Exchange sa (f . bt) {-# INLINE rmap #-} #ifndef SAFE ( #. ) _ = unsafeCoerce {-# INLINE ( #. ) #-} ( .# ) p _ = unsafeCoerce p {-# INLINE ( .# ) #-} #endif ------------------------------------------------------------------------------ -- Reversible ------------------------------------------------------------------------------ -- | This class provides a generalized notion of list reversal extended to other containers. class Reversing t where reversing :: t -> t instance Reversing [a] where reversing = Prelude.reverse instance Reversing StrictB.ByteString where reversing = StrictB.reverse instance Reversing LazyB.ByteString where reversing = LazyB.reverse instance Reversing StrictT.Text where reversing = StrictT.reverse instance Reversing LazyT.Text where reversing = LazyT.reverse instance Reversing (Vector.Vector a) where reversing = Vector.reverse instance Reversing (Seq a) where reversing = Seq.reverse instance Prim a => Reversing (Prim.Vector a) where reversing = Prim.reverse instance Unbox a => Reversing (Unbox.Vector a) where reversing = Unbox.reverse instance Storable a => Reversing (Storable.Vector a) where reversing = Storable.reverse