queuelike-1.0.6: Data/Queue/TrieQueue/Edge.hs

{-# LANGUAGE TypeFamilies, TypeOperators #-}

-- | As simple as it looks: an edge type constructor that performs comparisons only on its key.
module Data.Queue.TrieQueue.Edge ((:-)(..)) where

data k :- m = k :- m deriving (Show)

instance Eq k => Eq (k :- m) where
	(x :- _) == (y :- _) = x == y

instance Ord k => Ord (k :- m) where
	(x :- _) `compare` (y :- _) = x `compare` y
	(x :- _) <= (y :- _) = x <= y