The semigroups package
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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Properties
| Versions | 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 |
|---|---|
| Change log | CHANGELOG.markdown |
| Dependencies | base (>=2 && <5), binary, bytestring (>=0.9 && <1), bytestring-builder (>=0.10.4 && <1), containers (>=0.3 && <0.6), deepseq (>=1.1 && <1.5), ghc-prim, hashable (>=1.1 && <1.3), nats (>=0.1 && <2), tagged (>=0.4.4 && <1), text (>=0.10 && <2), transformers (>=0.2 && <0.6), transformers-compat (>=0.5 && <1), unordered-containers (==0.2.*) [details] |
| License | BSD3 |
| 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 repository | head: git clone git://github.com/ekmett/semigroups.git |
| Uploaded | Sun Apr 16 16:48:05 UTC 2017 by ryanglscott |
| Distributions | Arch:0.18.3, Debian:0.18.0.1, Fedora:0.18.2, FreeBSD:0.16.2.2, LTSHaskell:0.18.2, NixOS:0.18.3, Stackage:0.18.3, Tumbleweed:0.18.2 |
| Downloads | 300065 total (12395 in the last 30 days) |
| Votes | |
| Status | Docs available [build log] Last success reported on 2017-04-16 [all 1 reports] Hackage Matrix CI |
Flags
| Name | Description | Default | Type |
|---|---|---|---|
| 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 | Manual |
| binary | You can disable the use of the `binary` package using `-f-binary`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled | Manual |
| 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. | Enabled | Manual |
| bytestring-builder | Decides whether to use an older version of bytestring along with bytestring-builder or just a newer version of bytestring. This flag normally toggles automatically but you can use `-fbytestring-builder` or `-f-bytestring-builder` to explicitly change it. | Disabled | Automatic |
| containers | You can disable the use of the `containers` package using `-f-containers`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled | Manual |
| deepseq | You can disable the use of the `deepseq` package using `-f-deepseq`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled | Manual |
| tagged | You can disable the use of the `tagged` package using `-f-tagged`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled | Manual |
| 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. | Enabled | Manual |
| transformers | You can disable the use of the `transformers` and `transformers-compat` packages using `-f-transformers`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled | Manual |
| 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 | Manual |
Use -f <flag> to enable a flag, or -f -<flag> to disable that flag. More info
Downloads
- semigroups-0.18.3.tar.gz [browse] (Cabal source package)
- Package description (included in the package)
Readme for semigroups
Readme for semigroups-0.18.3
semigroups
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