# streams: Various Haskell 2010 stream comonads

Various Haskell 2010 stream comonads.
* Data.Stream.Future provides a coinductive anti-causal stream, or non-empty `ZipList`

. The comonad provides access to only the
tail of the stream. Like a conventional `ZipList`

, this is *not* a monad.

data Future a = Last a | a :< Future a

Data.Stream.Future.Skew provides a non-empty skew-binary random-access-list with the semantics of

`Data.Stream.Future`

. As with Data.Stream.Future this stream is not a`Monad`

, since the`Applicative`

instance zips streams of potentially differing lengths. The random-access-list structure provides a number of operations logarithmic access time, but makes`Data.Stream.Future.Skew.cons`

less productive. Where applicable Data.Stream.Infinite.Skew may be more efficient, due to a lazier and more efficient`Applicative`

instance.

Data.Stream.Infinite provides a coinductive infinite anti-causal stream. The

`Comonad`

provides access to the tail of the stream and the`Applicative`

zips streams together. Unlike`Future`

, infinite stream form a`Monad`

. The monad diagonalizes the`Stream`

, which is consistent with the behavior of the`Applicative`

, and the view of a`Stream`

as a isomorphic to the reader monad from the natural numbers. Being infinite in length, there is no`Alternative`

instance.

data Stream a = a :< Stream a

Data.Stream.Infinite.Skew provides an infinite skew-binary random-access-list with the semantics of Data.Stream.Infinite Since every stream is infinite, the

`Applicative`

instance can be considerably less strict than the corresponding instance for Data.Stream.Future.Skew and performs asymptotically better.

Data.Stream.Infinite.Functional.Zipper provides a bi-infinite sequence, represented as a pure function with an accumulating parameter added to optimize moving the current focus.

data Zipper a = !Integer :~ (Integer -> a)

Data.Stream.Supply provides a comonadic supply of unique values, which are generated impurely as the tree is explored.

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Versions | 0.1.1, 0.2, 0.3, 0.3.1, 0.4, 0.5.0, 0.5.1, 0.5.1.1, 0.5.1.2, 0.6.0, 0.6.0.1, 0.6.1.1, 0.6.1.2, 0.6.3, 0.7.0, 0.7.1, 0.7.2, 0.8.0, 0.8.0.1, 0.8.0.2, 0.8.0.3, 0.8.0.4, 0.8.1, 0.8.2, 3.0, 3.0.0.1, 3.0.1, 3.0.1.1, 3.1, 3.1.1, 3.2, 3.2.1, 3.3 |
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Change log | CHANGELOG.markdown |

Dependencies | adjunctions (>=4.0.1 && <5), base (==4.*), comonad (>=4 && <6), distributive (>=0.2.1 && <1), semigroupoids (>=4 && <6), semigroups (>=0.8.3.1 && <1) [details] |

License | BSD-3-Clause |

Copyright | Copyright 2011-2013 Edward Kmett Copyright 2010 Tony Morris, Oliver Taylor, Eelis van der Weegen Copyright 2007-2010 Wouter Swierstra, Bas van Dijk Copyright 2008 Iavor S. Diatchki |

Author | Edward A. Kmett |

Maintainer | Edward A. Kmett <ekmett@gmail.com> |

Category | Control, Comonads |

Home page | http://github.com/ekmett/streams/issues |

Source repo | head: git clone git://github.com/ekmett/streams.git |

Uploaded | by ryanglscott at Wed Jun 15 23:04:20 UTC 2016 |

Distributions | LTSHaskell:3.3, NixOS:3.3, Stackage:3.3 |

Downloads | 12801 total (144 in the last 30 days) |

Rating | 2.0 (votes: 1) [estimated by rule of succession] |

Your Rating | |

Status | Docs available [build log] Last success reported on 2016-11-23 [all 1 reports] Hackage Matrix CI |

## Modules

[Index]

## Downloads

- streams-3.3.tar.gz [browse] (Cabal source package)
- Package description (as included in the package)