semigroups: Anything that associates

[ algebra, bsd3, data, data-structures, library, math ] [ Propose Tags ]

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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NameDescriptionDefault
hashable

You can disable the use of the hashable package using `-f-hashable`.

Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

If disabled we will not supply instances of Hashable

Note: `-f-hashable` implies `-f-unordered-containers`, as we are necessarily not able to supply those instances as well.

Enabled
bytestring

You can disable the use of the bytestring package using `-f-bytestring`.

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containers

You can disable the use of the containers package using `-f-containers`.

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deepseq

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text

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unordered-containers

You can disable the use of the `unordered-containers` package using `-f-unordered-containers`.

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Enabled

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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
Dependencies base (>=2 && <5), bytestring (>=0.9 && <1), containers (>=0.3 && <0.6), deepseq (>=1.1 && <1.4), ghc-prim, hashable (>=1.1 && <1.3), nats (>=0.1 && <1), text (>=0.10 && <2), unordered-containers (>=0.2 && <0.3) [details]
License BSD-3-Clause
Copyright Copyright (C) 2011-2014 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 EdwardKmett at 2014-10-31T22:28:42Z
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 905 direct, 13724 indirect [details]
Downloads 483959 total (429 in the last 30 days)
Rating 2.75 (votes: 9) [estimated by Bayesian average]
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Status Docs uploaded by user
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Readme for semigroups-0.15.4

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semigroups

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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.

Semigroups appear all over the place, except in the Haskell Prelude, so they are packaged here.

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