[Haskell] RE: [Haskell-cafe] Interest in helping w/ Haskell standard

[Simon Peyton-Jones]

| In that context, how well-understood is the combination of
impredicative
| types via boxy types and a proper existential quantifier at the
moment?
| It's certainly something that has many uses in an industrial context.

Stephanie Weirich, Dimitrios Vytiniotis, and I are currently re-writing
our paper about type inference for impredicative polymorphism.  I don't
think there's any difficulty with existentials, at least when they are
wrapped in a data constructor (which is the way GHC deals with
existentials at the moment).  We'll have a draft done in a couple of
weeks.  (Until then the paper on my home page is still approximately
right.)
http://research.microsoft.com/%7Esimonpj/papers/boxy

Can you elaborate on what you had in mind in your last sentence above?

Simon