|Version 3 (modified by ijones, 10 years ago) (diff)|
Multi-parameter type classes
- Type classes: exploring the design space by Simon Peyton Jones, Mark Jones and Erik Meijer, Haskell Workshop 1997.
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.
- Are these useful without FunctionalDependencies?