I wrote:
What I don't like is that given a signature like
x :: a - a
there's no way to tell, looking at it in isolation, whether a is free or
bound in the type. [...]
Here's a completely different idea for solving this. It occurs to me that
there isn't all that much difference between
On Wed, Feb 08, 2006 at 05:48:24PM -, Simon Peyton-Jones wrote:
| b) A pattern type signature may bring into scope a skolem bound
|in the same pattern:
|data T where
| MkT :: a - (a-Int) - T
|f (MkT (x::a) f) = ...
|
|The skolem bound by
On Tue, Feb 07, 2006 at 08:15:19PM +, Ben Rudiak-Gould wrote:
Simon PJ thinks that Haskell' should include scoped type variables, and I
tend to agree. But I'm unhappy with one aspect of the way they're
implemented in GHC. What I don't like is that given a signature like
x :: a - a
| I think we should do the simplest thing that could possibly work,
| and then see if we really need more. By work, I mean a compatible
| extension of H98 that makes it possible to add type signatures for
| local bindings (which isn't always possible in H98). How about:
|
| * no implicit
Ben Rudiak-Gould wrote:
Simon PJ thinks that Haskell' should include scoped type variables, and
I tend to agree. But I'm unhappy with one aspect of the way they're
implemented in GHC. What I don't like is that given a signature like
x :: a - a
there's no way to tell, looking at it in
