content: {-# LANGUAGE CPP #-}
  #ifdef TRUSTWORTHY
  {-# LANGUAGE Trustworthy #-}
  #endif
  -----------------------------------------------------------------------------
  -- |
  -- Module      :  Silica.Internal.Iso
  -- Copyright   :  (C) 2012-2016 Edward Kmett
  -- License     :  BSD-style (see the file LICENSE)
  -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
  -- Stability   :  experimental
  -- Portability :  non-portable
  --
  ----------------------------------------------------------------------------
  module Silica.Internal.Iso
    ( Exchange(..)
    , Reversing(..)
    ) where
  
  import Data.Profunctor
  #ifndef SAFE
  import Data.Profunctor.Unsafe
  import Silica.Internal.Coerce
  #endif
  import Data.ByteString       as StrictB
  import Data.ByteString.Lazy  as LazyB
  import Data.List.NonEmpty    as NonEmpty
  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 'Silica.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
    ( #. ) _ = coerce'
    {-# INLINE ( #. ) #-}
    ( .# ) p _ = coerce 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 (NonEmpty.NonEmpty a) where
    reversing = NonEmpty.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
  