|Version 1 (modified by malcolm.wallace@…, 10 years ago) (diff)|
Automatic derivation of instances is jolly useful. Current problems are:
- Automatic derivation is only available for certain classes defined in the Prelude and standard libraries.
- There is no way to specify how to derive a user-defined class in the general case.
- Even in the absence of user-defined deriving, it should be easy for a 'newtype' decl to inherit some of the instances of its parent type, no matter where the class was defined, but this is currently only available as a ghc extension to haskell'98.
There are various extant proposals to enable the user-specification of the derivation of class instances.
- fill out a list