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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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`.

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

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containers

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

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

Enabled
deepseq

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

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text

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

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

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unordered-containers

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

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

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
Change log CHANGELOG.markdown
Dependencies base (>=2 && <4.9), bytestring (>=0.9 && <1), containers (>=0.3 && <0.6), deepseq (>=1.1 && <1.5), ghc-prim, hashable (>=1.1.1.0 && <1.3), nats (>=0.1 && <2), text (>=0.10 && <2), unordered-containers (>=0.2 && <0.3) [details]
License BSD-3-Clause
Copyright Copyright (C) 2011-2015 Edward A. Kmett
Author Edward A. Kmett
Maintainer Edward A. Kmett <ekmett@gmail.com>
Revised Revision 2 made by phadej at 2019-05-24T14:28:23Z
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 2015-03-07T04:27:13Z
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, 14008 indirect [details]
Downloads 487994 total (479 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 2015-03-07 [all 1 reports]

Readme for semigroups-0.16.2.1

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semigroups

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.

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