@@ -1,8 +1,6 @@
11{-# LANGUAGE CPP #-}
2−{-# LANGUAGE GeneralizedNewtypeDeriving #-}
3−{-# LANGUAGE StandaloneDeriving #-}
4−{-# LANGUAGE TypeFamilies #-}
52{-# LANGUAGE TypeOperators #-}
3+{-# LANGUAGE TypeFamilies #-}
64-- |
75-- Module:
86-- Data.Patch
@@ -13,10 +11,8 @@ module Data.Patch
1311 , module X
1412 ) where
1513
16−import Control.Applicative
1714import Data.Functor.Const (Const (..))
1815import Data.Functor.Identity
19−import Data.Map.Monoidal (MonoidalMap)
2016import Data.Proxy
2117#if !MIN_VERSION_base(4,11,0)
2218import Data.Semigroup (Semigroup (..))
@@ -39,12 +35,6 @@ import Data.Patch.MapWithMove as X
3935 , unsafePatchMapWithMove
4036 )
4137
42−-- | A 'Group' is a 'Monoid' where every element has an inverse.
43−class (Semigroup q, Monoid q) => Group q where
44− negateG :: q -> q
45− (~~) :: q -> q -> q
46− r ~~ s = r <> negateG s
47−
4838-- | An 'Additive' 'Semigroup' is one where (<>) is commutative
4939class Semigroup q => Additive q where
5040
@@ -55,52 +45,27 @@ instance Additive p => Patch (AdditivePatch p) where
5545 type PatchTarget (AdditivePatch p) = p
5646 apply (AdditivePatch p) q = Just $ p <> q
5747
58−instance (Ord k, Group q) => Group (MonoidalMap k q) where
59− negateG = fmap negateG
60−
61−instance (Ord k, Additive q) => Additive (MonoidalMap k q)
62−
6348-- | Trivial group.
64−instance Group () where
65− negateG _ = ()
66− _ ~~ _ = ()
6749instance Additive ()
6850
6951-- | Product group. A Pair of groups gives rise to a group
70−instance (Group a, Group b) => Group (a, b) where
71− negateG (a, b) = (negateG a, negateG b)
72− (a, b) ~~ (c, d) = (a ~~ c, b ~~ d)
7352instance (Additive a, Additive b) => Additive (a, b)
7453
7554-- See https://gitlab.haskell.org/ghc/ghc/issues/11135#note_111802 for the reason Compose is not also provided.
7655-- Base does not define Monoid (Compose f g a) so this is the best we can
7756-- really do for functor composition.
78−instance Group (f (g a)) => Group ((f :.: g) a) where
79− negateG (Comp1 xs) = Comp1 (negateG xs)
80− Comp1 xs ~~ Comp1 ys = Comp1 (xs ~~ ys)
8157instance Additive (f (g a)) => Additive ((f :.: g) a)
8258
8359-- | Product of groups, Functor style.
84−instance (Group (f a), Group (g a)) => Group ((f :*: g) a) where
85− negateG (a :*: b) = negateG a :*: negateG b
86− (a :*: b) ~~ (c :*: d) = (a ~~ c) :*: (b ~~ d)
8760instance (Additive (f a), Additive (g a)) => Additive ((f :*: g) a)
8861
8962-- | Trivial group, Functor style
90−instance Group (Proxy x) where
91− negateG _ = Proxy
92− _ ~~ _ = Proxy
9363instance Additive (Proxy x)
9464
9565-- | Const lifts groups into a functor.
96−deriving instance Group a => Group (Const a x)
9766instance Additive a => Additive (Const a x)
9867-- | Ideitnty lifts groups pointwise (at only one point)
99−deriving instance Group a => Group (Identity a)
10068instance Additive a => Additive (Identity a)
10169
10270-- | Functions lift groups pointwise.
103−instance Group b => Group (a -> b) where
104− negateG f = negateG . f
105− (~~) = liftA2 (~~)
10671instance Additive b => Additive (a -> b)