free: Monads for free
Free monads are useful for many tree-like structures and domain specific languages.
If f
is a Functor
then the free Monad
on f
is the type
of trees whose nodes are labeled with the constructors of f
. The word
"free" is used in the sense of "unrestricted" rather than "zero-cost":
Free f
makes no constraining assumptions beyond those given by f
and the
definition of Monad
. As used here it is a standard term from the
mathematical theory of adjoint functors.
Cofree comonads are dual to free monads. They provide convenient ways to talk
about branching streams and rose-trees, and can be used to annotate syntax
trees. The cofree comonad can be seen as a stream parameterized by a Functor
that controls its branching factor.
More information on free monads, including examples, can be found in the following blog posts: https://ekmett.github.io/reader/2008/monads-for-free/ https://ekmett.github.io/reader/2011/free-monads-for-less/
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- free-5.2.tar.gz [browse] (Cabal source package)
- Package description (revised from the package)
Note: This package has metadata revisions in the cabal description newer than included in the tarball. To unpack the package including the revisions, use 'cabal get'.
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Versions [RSS] | 0.1.0, 0.1.1, 0.2.0, 0.2.1, 0.2.2, 0.2.3, 1.8.0, 1.8.0.1, 1.8.0.3, 1.8.0.4, 2.0, 2.0.1, 2.0.1.1, 2.0.2, 2.0.3, 2.1, 2.1.1, 2.1.1.1, 2.2, 3.0, 3.1, 3.1.1, 3.2, 3.3, 3.3.0.1, 3.3.0.2, 3.3.1, 3.4, 3.4.1, 3.4.2, 4.0, 4.1, 4.2, 4.4, 4.5, 4.6, 4.6.1, 4.7, 4.7.1, 4.8, 4.8.0.1, 4.9, 4.10.0.1, 4.11, 4.12, 4.12.1, 4.12.2, 4.12.3, 4.12.4, 5, 5.0.1, 5.0.2, 5.1, 5.1.1, 5.1.2, 5.1.3, 5.1.4, 5.1.5, 5.1.6, 5.1.7, 5.1.8, 5.1.9, 5.1.10, 5.2 (info) |
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Change log | CHANGELOG.markdown |
Dependencies | base (>=4.9 && <5), bifunctor-classes-compat (>=0.1 && <0.2), comonad (>=5.0.8 && <6), containers (>=0.5.7.1 && <0.8), distributive (>=0.5.2 && <1), exceptions (>=0.10.4 && <0.11), indexed-traversable (>=0.1.1 && <0.2), mtl (>=2.2.2 && <2.4), profunctors (>=5.6.1 && <6), semigroupoids (>=5.3.5 && <7), template-haskell (>=2.11 && <2.23), th-abstraction (>=0.4.2.0 && <0.8), transformers (>=0.5 && <0.7), transformers-base (>=0.4.5.2 && <0.5) [details] |
Tested with | ghc ==8.0.2, ghc ==8.2.2, ghc ==8.4.4, ghc ==8.6.5, ghc ==8.8.4, ghc ==8.10.7, ghc ==9.0.2, ghc ==9.2.6, ghc ==9.4.4, ghc ==9.6.1 |
License | BSD-3-Clause |
Copyright | Copyright (C) 2008-2015 Edward A. Kmett |
Author | Edward A. Kmett |
Maintainer | Edward A. Kmett <ekmett@gmail.com> |
Revised | Revision 5 made by ryanglscott at 2024-05-16T11:05:55Z |
Category | Control, Monads |
Home page | http://github.com/ekmett/free/ |
Bug tracker | http://github.com/ekmett/free/issues |
Source repo | head: git clone git://github.com/ekmett/free.git |
Uploaded | by ryanglscott at 2023-03-12T18:42:24Z |
Distributions | Arch:5.1.10, Debian:5.1.3, Fedora:5.1.10, FreeBSD:4.12.1, LTSHaskell:5.2, NixOS:5.2, Stackage:5.2, openSUSE:5.2 |
Reverse Dependencies | 204 direct, 8038 indirect [details] |
Downloads | 259976 total (592 in the last 30 days) |
Rating | 2.5 (votes: 5) [estimated by Bayesian average] |
Your Rating | |
Status | Docs available [build log] Last success reported on 2023-03-12 [all 1 reports] |