Helium - Utrecht University's simplified Haskell - had scriptable "Type inference directives" so the creator of an EDSL was able to augment the type checker to provide better error messages, see:
Scripting the Type Inference Process Bastiaan Heeren Jurriaan Hage S. Doaitse Swierstra _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
