# countable: Countable, Searchable, Finite, Empty classes

Versions | 0.1, 0.2, 1.0 |
---|---|

Dependencies | base (==4.*) [details] |

License | BSD-3-Clause |

Copyright | Ashley Yakeley <ashley@semantic.org> |

Author | Ashley Yakeley <ashley@semantic.org> |

Maintainer | Ashley Yakeley <ashley@semantic.org> |

Category | Data |

Uploaded | by AshleyYakeley at Sun Sep 5 10:32:29 UTC 2010 |

Distributions | LTSHaskell:1.0, NixOS:1.0, Stackage:1.0, openSUSE:1.0 |

Downloads | 1187 total (18 in the last 30 days) |

Rating | (no votes yet) [estimated by rule of succession] |

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Status | Docs uploaded by user Build status unknown [no reports yet] Hackage Matrix CI |

`class Countable`

, for countable types`class AtLeastOneCountable`

, for countable types that have at least one value`class InfiniteCountable`

, for infinite countable types`class Searchable`

, for types that can be searched over. This turns out to include some infinite types, see http://math.andrej.com/2007/09/28/seemingly-impossible-functional-programs/.`class Finite`

, for finite types`class Empty`

, for empty types`data Nothing`

, an empty type

Some orphan instances:

`(Searchable a,Eq b) => Eq (a -> b)`

`(Finite t) => Foldable ((->) t)`

`(Finite a) => Traversable ((->) a)`

`(Show a,Finite a,Show b) => Show (a -> b)`

## Downloads

- countable-0.1.tar.gz [browse] (Cabal source package)
- Package description (as included in the package)