Portability | GHC only (-XKitchenSink) |
---|---|

Maintainer | Brent Yorgey <byorgey@cis.upenn.edu> |

Safe Haskell | Safe-Inferred |

Various utilities for the Unbound library.

# Documentation

class Foldable f => Collection f whereSource

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.

An empty collection. Must be the identity for `union`

.

Create a singleton collection.

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

An associative combining operation. The `Ord`

constraint is in
order to accommodate sets.

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

Collections must be functorial. The normal `Functor`

class
won't do because of the `Ord`

constraint on sets.

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 aSource

Combine a list of containers into one.

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

Create a collection from a list of elements.

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

Remove the `Nothing`

s from a collection.

A simple representation of multisets.

Foldable Multiset | |

Collection Multiset | Multisets are containers which preserve multiplicity but not ordering. |