Re: Restricted Data Types Now

On 2/8/06, oleg@pobox.com wrote:

It seems we can emulate the restricted data types in existing Haskell. ...

...

{-# OPTIONS -fglasgow-exts #-} {-# OPTIONS -fallow-undecidable-instances #-}

http://article.gmane.org/gmane.comp.lang.haskell.cvs.ghc/13500 Indicates that we will no longer need undecidable instances for this. Since we can check termination, and this simulates restricted data types with no core language changes, why not do it? Why not change the libraries in Haskell' to put formerly polymorphic variables as class parameters? Jim