5 Apr
2002
5 Apr
'02
3:06 a.m.
| Ah yes, silly me. What I had in mind, I suppose, was | something more along the lines of: | | foo :: Double -> (exists q . Foo q => q) Correct. Currently you can only express this by wrapping the existential in a constructor: data R = forall q. Foo q => MkR q foo :: Double -> R Mark Shields and I wrote a paper about doing more fully fledged existentials, but it's quite a significant chunk of work to implement. http://research.microsoft.com/~simonpj/Papers/first-class-modules Simon