Portability | non-portable (multi-param classes, functional dependencies) |
---|---|

Stability | experimental |

Maintainer | libraries@haskell.org |

Safe Haskell | Safe-Infered |

The MonadWriter class.

Inspired by the paper /Functional Programming with Overloading and Higher-Order Polymorphism/, Mark P Jones (http://web.cecs.pdx.edu/~mpj/pubs/springschool.html) Advanced School of Functional Programming, 1995.

# Documentation

class (Monoid w, Monad m) => MonadWriter w m | m -> w whereSource

Monoid w => MonadWriter w (Writer w) | |

Monoid w => MonadWriter w (Writer w) | |

MonadWriter w m => MonadWriter w (ReaderT r m) | |

(Error e, MonadWriter w m) => MonadWriter w (ErrorT e m) | |

MonadWriter w m => MonadWriter w (StateT s m) | |

MonadWriter w m => MonadWriter w (StateT s m) | |

(Monoid w, Monad m) => MonadWriter w (WriterT w m) | |

(Monoid w, Monad m) => MonadWriter w (WriterT w m) | |

Monoid w => MonadWriter w (RWS r w s) | |

Monoid w => MonadWriter w (RWS r w s) | |

(Monoid w, Monad m) => MonadWriter w (RWST r w s m) | |

(Monoid w, Monad m) => MonadWriter w (RWST r w s m) |

listens :: MonadWriter w m => (w -> b) -> m a -> m (a, b)Source

censor :: MonadWriter w m => (w -> w) -> m a -> m aSource