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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- Data
- List
- Data.List.NonEmpty
- Data.Semigroup
- List
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Manual Flags
| Name | Description | Default |
|---|---|---|
| hashable | You can disable the use of the 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 Note: `-f-hashable` implies `-f-unordered-containers`, as we are necessarily not able to supply those instances as well. | Enabled |
| binary | You can disable the use of the Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled |
| bytestring | You can disable the use of the Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled |
| containers | You can disable the use of the Disabling 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 Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled |
| tagged | You can disable the use of the Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled |
| template-haskell | You can disable the use of the `template-haskell` package using `-f-template-haskell`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled |
| text | You can disable the use of the Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled |
| transformers | You can disable the use of the Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. | Enabled |
| 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 |
Automatic Flags
| Name | Description | Default |
|---|---|---|
| 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 |
Use -f <flag> to enable a flag, or -f -<flag> to disable that flag. More info
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- semigroups-0.19.1.tar.gz [browse] (Cabal source package)
- Package description (as included in the package)
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[back to package description]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.
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