On Fri, May 04, 2001 at 07:56:24PM +0000, Marcin 'Qrczak' Kowalczyk wrote:
I would like to make pattern and result type signatures one-way matching, like in OCaml: a type variable just gives a name to the given part of the type, without constraining it any way - especially without "negative constraining", i.e. without yielding an error if it will be known more than that it's a possibly constrained type variable...
I'm not sure I understand here. One thing that occurred to me reading your e-mail was that maybe the implicit universal quantification over type variables is a bad idea, and maybe type variables should, by default, have pattern matching semantics. Whether or not this is a good idea abstractly, the way I imagine it, it would make almost all existing Haskell code invalid, so it can't be what you're proposing. Are you proposing that variables still be implicitly quantified in top-level bindings, but that elsewhere they have pattern-matching semantics? Best, Dylan Thurston