Safe Haskell | None |
---|---|

Language | Haskell2010 |

A carrier for `Writer`

effects. This carrier performs its append operations strictly and thus avoids the space leaks inherent in lazy writer monads. These appends are left-associative; as such, `[]`

is a poor choice of monoid for computations that entail many calls to `tell`

. The Seq or DList monoids may be a superior choice.

This implementation is based on a post Gabriel Gonzalez made to the Haskell mailing list: https://mail.haskell.org/pipermail/libraries/2013-March/019528.html

*Since: 1.0.0.0*

# Writer carrier

newtype WriterC w m a Source #

A space-efficient carrier for `Writer`

effects, implemented atop Control.Carrier.State.Strict.

*Since: 1.0.0.0*

#### Instances

MonadTrans (WriterC w) Source # | |

Defined in Control.Carrier.Writer.Strict | |

Monad m => Monad (WriterC w m) Source # | |

Functor m => Functor (WriterC w m) Source # | |

MonadFix m => MonadFix (WriterC w m) Source # | |

Defined in Control.Carrier.Writer.Strict | |

MonadFail m => MonadFail (WriterC w m) Source # | |

Defined in Control.Carrier.Writer.Strict | |

Monad m => Applicative (WriterC w m) Source # | |

Defined in Control.Carrier.Writer.Strict | |

MonadIO m => MonadIO (WriterC w m) Source # | |

Defined in Control.Carrier.Writer.Strict | |

(Alternative m, Monad m) => Alternative (WriterC w m) Source # | |

(Alternative m, Monad m) => MonadPlus (WriterC w m) Source # | |

(Monoid w, Algebra sig m) => Algebra (Writer w :+: sig) (WriterC w m) Source # | |

# Writer effect

module Control.Effect.Writer