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  • #4834

Closed
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Opened Dec 12, 2010 by gidyn@trac-gidyn
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Implement Functor => Applicative => Monad Hierarchy (aka AMP phase 3)

The standard class hierarchy is a consequence of Haskell's historical development, rather than logic. I would therefore like to propose a reform of the Functor, Applicative, and Monad type classes. The new hierarchy is logical, eliminates many duplicate names from the standard type class definitions, and removes the need for boilerplate Monad -> Applicative instance declarations.

The proposal is detailed in the wiki, along with an example of a legacy module to provide some backwards-compatibility.

Trac metadata
Trac field Value
Version 7.0.1
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component libraries/base
Test case
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Operating system
Architecture
Edited Mar 10, 2019 by Herbert Valerio Riedel

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Reference: ghc/ghc#4834