Unbound.Util

Various utilities for the Unbound library.

Documentation

class Foldable f => Collection f where

Collections are foldable types that support empty, singleton, union, and map operations. The result of a free variable calculation may be any collection. Instances are provided for lists, sets, and multisets.

Methods

emptyC :: f a

An empty collection. Must be the identity for union.

singleton :: a -> f a

Create a singleton collection.

union :: Ord a => f a -> f a -> f a

An associative combining operation. The Ord constraint is in order to accommodate sets.

cmap :: (Ord a, Ord b) => (a -> b) -> f a -> f b

Collections must be functorial. The normal Functor class won't do because of the Ord constraint on sets.

Instances

Collection []

Lists are containers under concatenation. Lists preserve ordering and multiplicity of elements.

Collection Set

Sets are containers under union, which preserve only occurrence, not multiplicity or ordering.

Collection Multiset

Multisets are containers which preserve multiplicity but not ordering.

unions :: (Ord a, Collection f) => [f a] -> f a

Combine a list of containers into one.

fromList :: (Ord a, Collection f) => [a] -> f a

Create a collection from a list of elements.

filterC :: (Collection f, Ord a) => f (Maybe a) -> f a

Remove the Nothings from a collection.

newtype Multiset a

A simple representation of multisets.

Constructors

Multiset (Map a Int)

Instances

Foldable Multiset

Collection Multiset

Multisets are containers which preserve multiplicity but not ordering.

disjoint :: Ord a => Set a -> Set a -> Bool