Copyright	(c) Conal Elliott 2007
License	BSD3
Maintainer	conal@conal.net
Stability	experimental
Portability	portable
Safe Haskell	None
Language	Haskell98

Data.Partial

Contents

Partial values
Support for arrow partial value arrow
Orphan instances

Description

A monoid Partial of partial values. See the [Teaser] and [Solution] blog posts.

Teaser: http://conal.net/blog/posts/a-type-for-partial-values
Solution: http://conal.net/blog/posts/implementing-a-type-for-partial-values

Also defines a FunAble instance, so that FunA Partial is an arrow.

Synopsis

Partial values

type Partial = Endo Source #

Partial value. Represented an endomorphism, which is a Monoid under id and '(.)'. Then mempty is the completely undefined value, and in u `'mappend'@` v, v selectively replaces parts of u@. The Endo instances for Pair, Unpair, Copair, Unfun, and Cofun are all very useful on partial values.

type PartialX a b = Partial a -> Partial b Source #

valp :: c -> Partial c Source #

Treat a full value as a partial one. Fully overrides any "previous" (earlier argument to mappend) partial value.

pval :: Partial c -> c Source #

Force a partial value into a full one, filling in bottom for any missing parts.

pUnElt :: Functor f => PartialX a (f a) Source #

Inverse to "element" access, on all elements. A way to inject some info about every element. For f, consider '[]', (->) a, Event, etc.

pUnArg :: PartialX u (u -> v) Source #

Provide in info about a function argument

pUnRes :: PartialX v (u -> v) Source #

Provide info about a function result

pUnSrc :: PartialX a ((a -> b) -> o) Source #

Inject a partial argument-source into a partial function-sink.

Support for arrow partial value arrow

Orphan instances

FunAble Partial Source #