[Haskell-cafe] closed classes

Ketil Malde ketil+haskell at ii.uib.no
Fri Aug 6 10:39:23 EDT 2004

Duncan Coutts <duncan.coutts at worcester.oxford.ac.uk> writes:

> closed class GConfValue v where


    module Closed(foo) where
    class C a where foo = ...
    instance C ...
    module Main where
    import Closed

do what you want?  You can only use existing instances of C, but not
declare them (outside of the Closed module), IIUC.

If I haven't seen further, it is by standing in the footprints of giants

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