@@ -23,7 +23,6 @@ import Data.Semigroup (Semigroup (..))
24import GHC.Generics
24import GHC.Generics
26−import Data.Semigroup.Additive as X
27import Data.Patch.Class as X
26import Data.Patch.Class as X
28import Data.Patch.DMap as X hiding (getDeletions)
27import Data.Patch.DMap as X hiding (getDeletions)
29import Data.Patch.DMapWithMove as X
28import Data.Patch.DMapWithMove as X
@@ -46,6 +45,9 @@ class (Semigroup q, Monoid q) => Group q where
46 (~~) :: q -> q -> q
45 (~~) :: q -> q -> q
47 r ~~ s = r <> negateG s
46 r ~~ s = r <> negateG s
48+-- | An 'Additive' 'Semigroup' is one where (<>) is commutative
49+class Semigroup q => Additive q where
49-- | The elements of an 'Additive' 'Semigroup' can be considered as patches of their own type.
51-- | The elements of an 'Additive' 'Semigroup' can be considered as patches of their own type.
50newtype AdditivePatch p = AdditivePatch { unAdditivePatch :: p }
52newtype AdditivePatch p = AdditivePatch { unAdditivePatch :: p }
@@ -56,15 +58,19 @@ instance Additive p => Patch (AdditivePatch p) where
56instance (Ord k, Group q) => Group (MonoidalMap k q) where
58instance (Ord k, Group q) => Group (MonoidalMap k q) where
57 negateG = fmap negateG
59 negateG = fmap negateG
61+instance (Ord k, Additive q) => Additive (MonoidalMap k q)
59-- | Trivial group.
63-- | Trivial group.
60instance Group () where
64instance Group () where
61 negateG _ = ()
65 negateG _ = ()
62 _ ~~ _ = ()
66 _ ~~ _ = ()
64-- | Product group. A Pair of groups gives rise to a group
69-- | Product group. A Pair of groups gives rise to a group
65instance (Group a, Group b) => Group (a, b) where
70instance (Group a, Group b) => Group (a, b) where
66 negateG (a, b) = (negateG a, negateG b)
71 negateG (a, b) = (negateG a, negateG b)
67 (a, b) ~~ (c, d) = (a ~~ c, b ~~ d)
72 (a, b) ~~ (c, d) = (a ~~ c, b ~~ d)
73+instance (Additive a, Additive b) => Additive (a, b)
69-- See https://gitlab.haskell.org/ghc/ghc/issues/11135#note_111802 for the reason Compose is not also provided.
75-- See https://gitlab.haskell.org/ghc/ghc/issues/11135#note_111802 for the reason Compose is not also provided.
70-- Base does not define Monoid (Compose f g a) so this is the best we can
76-- Base does not define Monoid (Compose f g a) so this is the best we can
@@ -72,24 +78,29 @@ instance (Group a, Group b) => Group (a, b) where
72instance Group (f (g a)) => Group ((f :.: g) a) where
78instance Group (f (g a)) => Group ((f :.: g) a) where
73 negateG (Comp1 xs) = Comp1 (negateG xs)
79 negateG (Comp1 xs) = Comp1 (negateG xs)
74 Comp1 xs ~~ Comp1 ys = Comp1 (xs ~~ ys)
80 Comp1 xs ~~ Comp1 ys = Comp1 (xs ~~ ys)
81+instance Additive (f (g a)) => Additive ((f :.: g) a)
76-- | Product of groups, Functor style.
83-- | Product of groups, Functor style.
77instance (Group (f a), Group (g a)) => Group ((f :*: g) a) where
84instance (Group (f a), Group (g a)) => Group ((f :*: g) a) where
78 negateG (a :*: b) = negateG a :*: negateG b
85 negateG (a :*: b) = negateG a :*: negateG b
79 (a :*: b) ~~ (c :*: d) = (a ~~ c) :*: (b ~~ d)
86 (a :*: b) ~~ (c :*: d) = (a ~~ c) :*: (b ~~ d)
87+instance (Additive (f a), Additive (g a)) => Additive ((f :*: g) a)
81-- | Trivial group, Functor style
89-- | Trivial group, Functor style
82instance Group (Proxy x) where
90instance Group (Proxy x) where
83 negateG _ = Proxy
91 negateG _ = Proxy
84 _ ~~ _ = Proxy
92 _ ~~ _ = Proxy
93+instance Additive (Proxy x)
86-- | Const lifts groups into a functor.
95-- | Const lifts groups into a functor.
87deriving instance Group a => Group (Const a x)
96deriving instance Group a => Group (Const a x)
88−
97+instance Additive a => Additive (Const a x)
89-- | Identity lifts groups pointwise (at only one point)
98-- | Identity lifts groups pointwise (at only one point)
90deriving instance Group a => Group (Identity a)
99deriving instance Group a => Group (Identity a)
100+instance Additive a => Additive (Identity a)
92-- | Functions lift groups pointwise.
102-- | Functions lift groups pointwise.
93instance Group b => Group (a -> b) where
103instance Group b => Group (a -> b) where
94 negateG f = negateG . f
104 negateG f = negateG . f
95 (~~) = liftA2 (~~)
105 (~~) = liftA2 (~~)
106+instance Additive b => Additive (a -> b)