-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | A Groupoid class
--   
--   A groupoid is structure consisting of a set of elements (here a
--   Haskell type) and a binary operator (in present case the function
--   <a>gappend</a>).
--   
--   It is comparable to the Monoid typeclass, but there is no obligation
--   that the set supports a neutral element (mempty in Data.Monoid).
--   
--   In geometry, bounding boxes (represented as two points - bottom-left
--   corner and top-right corner) give an example where a groupoid may be
--   more satisfying than a monoid. The union operation on bounding boxes
--   is essential to track the extent of shapes after their
--   superimposition. To fit bounding box union into the Monoid typeclass
--   one can do a clever trick representing mempty with the bottom-left
--   corner at positive infinity and the top-right corner at negative
--   infinity, the standard implementation of union which uses min and max
--   will still proceed to identify the extreme corners correctly. This is
--   nice enough if the bounding box coordinates are represented by
--   Doubles, but a problem if they are Ints (say representing grid
--   coordinates) - one might decide it is better simply to consider
--   concrete bounding boxes and not their empty/infinite cousins.
@package groupoid
@version 0.1.0


-- | Groupoid - a set with a binary operator, more general than monoid as
--   there is no obligation to have a neutral element (i.e mempty in
--   Data.Monoid).
module Data.Groupoid
class Groupoid a
gappend :: Groupoid a => a -> a -> a
gconcat :: Groupoid a => [a] -> a
instance Groupoid (Last a)
instance Groupoid (First a)
instance Groupoid a => Groupoid (Maybe a)
instance Num a => Groupoid (Product a)
instance Num a => Groupoid (Sum a)
instance Groupoid Any
instance Groupoid All
instance Groupoid (Endo a)
instance Groupoid a => Groupoid (Dual a)
instance Groupoid Ordering
instance (Groupoid a, Groupoid b, Groupoid c, Groupoid d, Groupoid e) => Groupoid (a, b, c, d, e)
instance (Groupoid a, Groupoid b, Groupoid c, Groupoid d) => Groupoid (a, b, c, d)
instance (Groupoid a, Groupoid b, Groupoid c) => Groupoid (a, b, c)
instance (Groupoid a, Groupoid b) => Groupoid (a, b)
instance Groupoid ()
instance Groupoid (a -> a)
instance Groupoid [a]