TypeCompose For Mac Publisher's description
from Conal Elliott
Type composition classes and instances in Haskell
TypeCompose is a free and open source Haskell library that provides some classes and instances for forms of type composition, as well as some other modules.
The Control.Compose module includes:
В· Various type compositions (unary/unary, binary/unary, etc). Most are from Applicative Programming with Effects. In particular, g `O` f composes functors in to functors and applicative functors (AFs) into AFs. (In contrast, monads do not in general compose.) Composition makes AF-based programming simple and elegant, partly because we don't need an AF counterpart to monad transformers.
В· Cofunctors (contravariant functors). Great for "consumer" types, just as functors suit "producer" (container) types. There are several composition options.
В· Type argument flip. Handy for cofunctors: use Flip (->) o, for (-> o).
В· Constructor in pairs: (f a, g a).
В· Constructor in arrows/functions: f a ~> g a.
System Requirements:No special requirements.
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