# compose-trans: Composable monad transformers

A version of monad transformers that (a) allows one to convince the type checker that transformer application is a monad, and (b) doesn't need lots of boilerplate to add a new transformer. It's supposed to play nicely with `Control.Monad.Trans`

.

In order to make a new transformer (say, `T`

) an instance of `TransM`

(`TransP`

, `TransF`

) class, all you have to do is:

define

`instance MonadTrans T`

— which you've probably done alreadydefine

`instance Monad m => Monad (T m)`

— also something quite common (for`TransP`

and`TransF`

you'd need another instance for`MonadPlus`

and`MonadFix`

, respectively).write

`instance Trans T where transMInst = instM`

— which is exactly one line of boilerplate. Sorry for that.

After that, you can use your new and shiny transformer in compositions, like `ReaderT Char :. T :. WriterT String`

— and such a composition would automagically become a monad transmormer.

Versions [faq] | 0.0, 0.1 |
---|---|

Dependencies | base (>=2 && <=4), mtl [details] |

License | BSD-3-Clause |

Author | Miguel Mitrofanov |

Maintainer | miguelimo38@yandex.ru |

Category | Monads |

Uploaded | by MiguelMitrofanov at 2009-08-17T04:13:54Z |

Distributions | NixOS:0.1 |

Downloads | 1678 total (2 in the last 30 days) |

Rating | (no votes yet) [estimated by Bayesian average] |

Your Rating | |

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

## Modules

[Index]

## Downloads

- compose-trans-0.0.tar.gz [browse] (Cabal source package)
- Package description (as included in the package)