wiki:MultiParamTypeClasses

Version 3 (modified by ijones, 8 years ago) (diff)

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Multi-parameter type classes

See ExtensionDescriptionHowto for information on how to write these extension descriptions. Please add any new extensions to the list of HaskellExtensions.

Brief Explanation

References

Multiparameter type classes are used twice in the base package of the Haskell hierarchical libraries:

class HasBounds a => IArray a e
class (HasBounds a, Monad m) => MArray a e m

The instances supplied do not overlap.

They also seem to be needed, with OverlappingInstances, for container and monad classes.

Pros

Cons