The functor-apply package

[Tags:bsd3, deprecated, library]
Deprecated. in favor of semigroupoids

Provides a wide array of semigroup based Functors.

When working with comonads you often have the <*> portion of an Applicative, but not the pure. This was captured in Uustalu and Vene's "Essence of Dataflow Programming" in the form of the ComonadZip class in the days before Applicative. Apply provides a weaker invariant, but for the comonads used for data flow programming (found in the streams package), this invariant is preserved.

Ideally the following relationships would hold:

 Traversable <---- Foldable <--- Functor ------> Alt ---------> Plus
      |               |            |                              |
      v               v            v                              v
 Traversable1 <--- Foldable1     Apply --------> Applicative -> Alternative
                                   |               |              |
                                   v               v              v
                                 Bind ---------> Monad -------> MonadPlus



 Bitraversable <-- Bifoldable <- Bifunctor                      Semigroupoid
     |                  |          |                              |
     v                  v          v                              v
 Bitraversable1 <- Bifoldable1   Biapply                        Category
                                                                  |
                                                                  v
                                                                Arrow

This lets us remove many of the restrictions from various monad transformers as in many cases the binding operation or <*> operation does not require them.

Finally, to work with these weaker structures it is beneficial to have containers that can provide stronger guarantees about their contents, so versions of Traversable and Foldable that can be folded with just a Semigroup are added.

Properties

Versions 0.5.0, 0.6.0, 0.7.0, 0.7.1, 0.7.2, 0.7.3, 0.7.4, 0.7.4.1, 0.9.0, 0.9.1, 0.9.2, 0.9.3, 0.10.0, 0.10.0.1, 0.10.0.2, 0.10.0.3, 0.10.1, 0.10.3, 0.10.4, 0.10.5, 0.11
Dependencies base (>=4 && <4.4), bifunctors (==0.1.*), comonad (>=0.9.0 && <1.0), containers (>=0.4.0 && <0.5), semigroups (>=0.3.2 && <0.4), transformers (>=0.2.0 && <0.3) [details]
License BSD3
Copyright Copyright (C) 2011 Edward A. Kmett
Author Edward A. Kmett
Maintainer Edward A. Kmett <ekmett@gmail.com>
Stability provisional
Category Control, Comonads
Home page http://comonad.com/reader/
Uploaded Sun Jan 30 11:05:01 UTC 2011 by EdwardKmett
Distributions NixOS:0.11
Downloads 4298 total (111 in the last 30 days)
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Status Docs uploaded by user
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