semigroups: Anything that associates

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In mathematics, a semigroup is an algebraic structure consisting of a set together with an associative binary operation. A semigroup generalizes a monoid in that there might not exist an identity element. It also (originally) generalized a group (a monoid with all inverses) to a type where every element did not have to have an inverse, thus the name semigroup.


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Versions [RSS] 0.1.0, 0.2.0, 0.3.0, 0.3.1, 0.3.2, 0.3.3, 0.3.4, 0.3.4.1, 0.3.4.2, 0.4.0, 0.5.0, 0.5.0.1, 0.5.0.2, 0.6, 0.6.1, 0.7.0, 0.7.1, 0.7.1.1, 0.7.1.2, 0.8, 0.8.0.1, 0.8.2, 0.8.3, 0.8.3.1, 0.8.3.2, 0.8.4, 0.8.4.1, 0.8.5, 0.9, 0.9.1, 0.9.2, 0.10, 0.11, 0.12, 0.12.0.1, 0.12.1, 0.12.2, 0.13, 0.13.0.1, 0.14, 0.15, 0.15.1, 0.15.2, 0.15.3, 0.15.4, 0.16, 0.16.0.1, 0.16.1, 0.16.2, 0.16.2.1, 0.16.2.2, 0.17, 0.17.0.1, 0.18, 0.18.0.1, 0.18.1, 0.18.2, 0.18.3, 0.18.4, 0.18.5, 0.19, 0.19.1, 0.19.2, 0.20
Change log CHANGELOG.markdown
Dependencies base (>=2 && <5), binary, bytestring (>=0.9 && <1), bytestring-builder (>=0.10.4 && <1), containers (>=0.3 && <0.7), deepseq (>=1.1 && <1.5), ghc-prim, hashable (>=1.2.5.0 && <1.4), nats (>=0.1 && <2), tagged (>=0.4.4 && <1), template-haskell (>=2.5.0.0 && <2.11), text (>=0.10 && <2), transformers (>=0.2 && <0.6), transformers-compat (>=0.5 && <1), unordered-containers (>=0.2 && <0.3) [details]
Tested with ghc ==7.0.4, ghc ==7.2.2, ghc ==7.4.2, ghc ==7.6.3, ghc ==7.8.4, ghc ==7.10.3, ghc ==8.0.2, ghc ==8.2.2, ghc ==8.4.4, ghc ==8.6.5, ghc ==8.8.1
License BSD-3-Clause
Copyright Copyright (C) 2011-2015 Edward A. Kmett
Author Edward A. Kmett
Maintainer Edward A. Kmett <ekmett@gmail.com>
Category Algebra, Data, Data Structures, Math
Home page http://github.com/ekmett/semigroups/
Bug tracker http://github.com/ekmett/semigroups/issues
Source repo head: git clone git://github.com/ekmett/semigroups.git
Uploaded by ryanglscott at 2019-05-10T13:57:15Z
Distributions Debian:0.19.1, Fedora:0.20, FreeBSD:0.16.2.2, LTSHaskell:0.20, NixOS:0.20, Stackage:0.20, openSUSE:0.20
Reverse Dependencies 908 direct, 14015 indirect [details]
Downloads 488050 total (416 in the last 30 days)
Rating 2.75 (votes: 9) [estimated by Bayesian average]
Your Rating
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Status Docs available [build log]
Last success reported on 2019-05-10 [all 1 reports]

Readme for semigroups-0.19

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semigroups

Hackage Build Status

Haskellers are usually familiar with monoids. A monoid has an appending operation <> or mappend and an identity element mempty. A Semigroup has an append <>, but does not require an mempty element. A Monoid can be made a Semigroup with just instance Semigroup MyMonoid

More formally, a semigroup is an algebraic structure consisting of a set together with an associative binary operation. A semigroup generalizes a monoid in that there might not exist an identity element. It also (originally) generalized a group (a monoid with all inverses) to a type where every element did not have to have an inverse, thus the name semigroup.

Data.Semigroup and Data.List.NonEmpty were added to base as of 4.9.0.0. This package now offers a backwards-compatible API and some tools for deriving semigroups with generics.

Contact Information

Contributions and bug reports are welcome!

Please feel free to contact me through github or on the #haskell IRC channel on irc.freenode.net.

-Edward Kmett