# The free-functors package

A free functor is a left adjoint to a forgetful functor. It used to be the case that the only category that was easy to work with in Haskell was Hask itself, so there were no interesting forgetful functors.

But the new ConstraintKinds feature of GHC provides an easy way of creating subcategories of Hask. That brings interesting opportunities for free (and cofree) functors.

The examples directory contains an implementation of non-empty lists as free semigroups, and automata as free actions. The standard example of free higher order functors is free monads, and this definition can be found in Data.Functor.HFree.

## Properties

Versions | 0, 0.1, 0.1.1, 0.1.2, 0.2, 0.3, 0.4, 0.4.1, 0.5, 0.6, 0.6.1, 0.6.1.1, 0.6.2, 0.6.3, 0.6.3.1, 0.6.3.2, 0.6.3.3, 0.6.4, 0.6.4.1, 0.6.5, 0.7, 0.7.1, 0.7.2, 0.8, 0.8.1 |
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Dependencies | algebraic-classes (>=0.1 && <0.3), base (>=4.4 && <5), comonad (==3.0.*), constraints (>=0.3.2 && <0.4), transformers (>=0.2.0.0 && <0.4), void (>=0.4 && <0.7) [details] |

License | BSD3 |

Author | Sjoerd Visscher |

Maintainer | sjoerd@w3future.com |

Category | Data, Math |

Home page | https://github.com/sjoerdvisscher/free-functors |

Bug tracker | https://github.com/sjoerdvisscher/free-functors/issues |

Source repository | head: git clone git://github.com/sjoerdvisscher/free-functors.git |

Uploaded | Sun Apr 21 16:19:22 UTC 2013 by SjoerdVisscher |

Distributions | NixOS:0.8.1 |

Downloads | 4538 total (102 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 |

## Downloads

- free-functors-0.4.tar.gz [browse] (Cabal source package)
- Package description (included in the package)