1{-# LANGUAGE CPP #-}
2{-# LANGUAGE DeriveDataTypeable #-}
3{-# LANGUAGE EmptyDataDecls #-}
4{-# LANGUAGE FlexibleContexts #-}
5{-# LANGUAGE StandaloneDeriving #-}
6{-# LANGUAGE TypeFamilies #-}
7{-# LANGUAGE TypeOperators #-}
8
9#if __GLASGOW_HASKELL__ >= 702
10{-# LANGUAGE DeriveGeneric #-}
11#endif
12
13#if __GLASGOW_HASKELL__ >= 706
14{-# LANGUAGE PolyKinds #-}
15#endif
16
17#if __GLASGOW_HASKELL__ >= 708
18{-# LANGUAGE Safe #-}
19#elif __GLASGOW_HASKELL__ >= 702
20{-# LANGUAGE Trustworthy #-}
21#endif
22#include "bifunctors-common.h"
23
24-----------------------------------------------------------------------------
25-- |
26-- Copyright   :  (C) 2008-2016 Edward Kmett
27-- License     :  BSD-style (see the file LICENSE)
28--
29-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
30-- Stability   :  provisional
31-- Portability :  portable
32--
33----------------------------------------------------------------------------
34module Data.Bifunctor.Biff
35  ( Biff(..)
36  ) where
37
38#if __GLASGOW_HASKELL__ < 710
39import Control.Applicative
40#endif
41
42import Data.Biapplicative
43import Data.Bifoldable
44import Data.Bitraversable
45
46#if __GLASGOW_HASKELL__ < 710
47import Data.Foldable
48import Data.Monoid
49import Data.Traversable
50#endif
51
52#if __GLASGOW_HASKELL__ >= 708
53import Data.Typeable
54#endif
55
56#if __GLASGOW_HASKELL__ >= 702
57import GHC.Generics
58#endif
59
60#if LIFTED_FUNCTOR_CLASSES
61import Data.Functor.Classes
62#endif
63
64-- | Compose two 'Functor's on the inside of a 'Bifunctor'.
65newtype Biff p f g a b = Biff { runBiff :: p (f a) (g b) }
66  deriving ( Eq, Ord, Show, Read
67#if __GLASGOW_HASKELL__ >= 702
68           , Generic
69#endif
70#if __GLASGOW_HASKELL__ >= 708
71           , Typeable
72#endif
73           )
74#if __GLASGOW_HASKELL__ >= 702
75# if __GLASGOW_HASKELL__ >= 708
76deriving instance Functor (p (f a)) => Generic1 (Biff p f g a)
77# else
78data BiffMetaData
79data BiffMetaCons
80data BiffMetaSel
81
82instance Datatype BiffMetaData where
83    datatypeName = const "Biff"
84    moduleName = const "Data.Bifunctor.Biff"
85
86instance Constructor BiffMetaCons where
87    conName = const "Biff"
88    conIsRecord = const True
89
90instance Selector BiffMetaSel where
91    selName = const "runBiff"
92
93instance Functor (p (f a)) => Generic1 (Biff p f g a) where
94    type Rep1 (Biff p f g a) = D1 BiffMetaData (C1 BiffMetaCons
95        (S1 BiffMetaSel (p (f a) :.: Rec1 g)))
96    from1 = M1 . M1 . M1 . Comp1 . fmap Rec1 . runBiff
97    to1 = Biff . fmap unRec1 . unComp1 . unM1 . unM1 . unM1
98# endif
99#endif
100
101#if LIFTED_FUNCTOR_CLASSES
102instance (Eq2 p, Eq1 f, Eq1 g, Eq a) => Eq1 (Biff p f g a) where
103  liftEq = liftEq2 (==)
104instance (Eq2 p, Eq1 f, Eq1 g) => Eq2 (Biff p f g) where
105  liftEq2 f g (Biff x) (Biff y) = liftEq2 (liftEq f) (liftEq g) x y
106
107instance (Ord2 p, Ord1 f, Ord1 g, Ord a) => Ord1 (Biff p f g a) where
108  liftCompare = liftCompare2 compare
109instance (Ord2 p, Ord1 f, Ord1 g) => Ord2 (Biff p f g) where
110  liftCompare2 f g (Biff x) (Biff y) = liftCompare2 (liftCompare f) (liftCompare g) x y
111
112instance (Read2 p, Read1 f, Read1 g, Read a) => Read1 (Biff p f g a) where
113  liftReadsPrec = liftReadsPrec2 readsPrec readList
114instance (Read2 p, Read1 f, Read1 g) => Read2 (Biff p f g) where
115  liftReadsPrec2 rp1 rl1 rp2 rl2 p = readParen (p > 10) $ \s0 -> do
116    ("Biff",    s1) <- lex s0
117    ("{",       s2) <- lex s1
118    ("runBiff", s3) <- lex s2
119    (x,         s4) <- liftReadsPrec2 (liftReadsPrec rp1 rl1) (liftReadList rp1 rl1)
120                                      (liftReadsPrec rp2 rl2) (liftReadList rp2 rl2) 0 s3
121    ("}",       s5) <- lex s4
122    return (Biff x, s5)
123
124instance (Show2 p, Show1 f, Show1 g, Show a) => Show1 (Biff p f g a) where
125  liftShowsPrec = liftShowsPrec2 showsPrec showList
126instance (Show2 p, Show1 f, Show1 g) => Show2 (Biff p f g) where
127  liftShowsPrec2 sp1 sl1 sp2 sl2 p (Biff x) = showParen (p > 10) $
128      showString "Biff {runBiff = "
129    . liftShowsPrec2 (liftShowsPrec sp1 sl1) (liftShowList sp1 sl1)
130                     (liftShowsPrec sp2 sl2) (liftShowList sp2 sl2) 0 x
131    . showChar '}'
132#endif
133
134instance (Bifunctor p, Functor f, Functor g) => Bifunctor (Biff p f g) where
135  first f = Biff . first (fmap f) . runBiff
136  {-# INLINE first #-}
137  second f = Biff . second (fmap f) . runBiff
138  {-# INLINE second #-}
139  bimap f g = Biff . bimap (fmap f) (fmap g) . runBiff
140  {-# INLINE bimap #-}
141
142instance (Bifunctor p, Functor g) => Functor (Biff p f g a) where
143  fmap f = Biff . second (fmap f) . runBiff
144  {-# INLINE fmap #-}
145
146instance (Biapplicative p, Applicative f, Applicative g) => Biapplicative (Biff p f g) where
147  bipure a b = Biff (bipure (pure a) (pure b))
148  {-# INLINE bipure #-}
149
150  Biff fg <<*>> Biff xy = Biff (bimap (<*>) (<*>) fg <<*>> xy)
151  {-# INLINE (<<*>>) #-}
152
153instance (Bifoldable p, Foldable g) => Foldable (Biff p f g a) where
154  foldMap f = bifoldMap (const mempty) (foldMap f) . runBiff
155  {-# INLINE foldMap #-}
156
157instance (Bifoldable p, Foldable f, Foldable g) => Bifoldable (Biff p f g) where
158  bifoldMap f g = bifoldMap (foldMap f) (foldMap g) . runBiff
159  {-# INLINE bifoldMap #-}
160
161instance (Bitraversable p, Traversable g) => Traversable (Biff p f g a) where
162  traverse f = fmap Biff . bitraverse pure (traverse f) . runBiff
163  {-# INLINE traverse #-}
164
165instance (Bitraversable p, Traversable f, Traversable g) => Bitraversable (Biff p f g) where
166  bitraverse f g = fmap Biff . bitraverse (traverse f) (traverse g) . runBiff
167  {-# INLINE bitraverse #-}
168