The acme-cofunctor package

[ Tags: acme, bsd3, library ] [ Propose Tags ]

A Cofunctor is a structure from category theory dual to Functor.

A Functor is defined by the operation fmap:

fmap :: (a -> b) -> (f a -> f b)

This means that its dual must be defined by the following operation:

cofmap :: (b -> a) -> (f b -> f a)

Since beginning his investigations, the author of this package has discovered that this pattern is at least as commonly used as Functor. In fact, many ubiquitous Haskell types (e.g. [], Maybe, ((->) a) turn out to have a Cofunctor instance.


Dependencies base (==4.*) [details]
License BSD3
Copyright 2014 Jasper Van der Jeugt
Author Jasper Van der Jeugt <>
Maintainer Jasper Van der Jeugt <>
Category Acme
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Source repo head: git clone
Uploaded Fri Nov 28 16:23:30 UTC 2014 by JasperVanDerJeugt
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Downloads 716 total (17 in the last 30 days)
Rating 2.0 (votes: 2) [estimated by rule of succession]
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