groups 0.1.0.1 → 0.2.0.0

raw patch · 2 files changed

+7/−3 lines, 2 files

Files

groups.cabal +1/−1
src/Data/Group.hs +6/−2

groups.cabal view

@@ -1,5 +1,5 @@ name:                groups-version:             0.1.0.1+version:             0.2.0.0 synopsis:            Haskell 98 groups description:            Haskell 98 groups. A group is a monoid with invertibility.

src/Data/Group.hs view

@@ -4,7 +4,8 @@  -- |A 'Group' is a 'Monoid' plus a function, 'invert', such that:  ----- @a <> invert a == mempty@+-- @a \<> invert a == mempty@+-- @invert a \<> a == mempty@ class Monoid m => Group m where   invert :: m -> m   @@ -22,7 +23,10 @@ instance Group a => Group (Dual a) where   invert = Dual . invert . getDual   {-# INLINE invert #-}-  ++instance Group b => Group (a -> b) where+  invert f = invert . f+ instance (Group a, Group b) => Group (a, b) where   invert (a, b) = (invert a, invert b)