| I can also imagine predicates that do not mention locally-quantified
| variables - the assumption must be that they mention variables bound on
| the LHS of the datatype decl instead? e.g. the Show predicate here:
|
| data Foo a b = Foo a b
| | Bar (forall c . (Show b,
Andres Loeh wrote:
I cannot see how an empty list of tyvars is useful or desirable in
practice:
data Foo = Foo (forall . Int)
is equivalent to just
data Foo = Foo Int
so why bother to permit the former? It probably indicates some error in
the thinking of the programmer, so the
The only reasons that I could see in favor of allowing empty foralls
is that it might be easier to automatically generate code. Haskell
seems to be a bit inconsistent in how it treats empty constructs. For
example, empty let and empty where seems to be allowed, but not an
empty case?
On Jan 26, 2007, at 6:22 PM, Claus Reinke wrote:
2) There are other reasons why I want to use Haskell-98 and
would like to be able to use other compilers. Thus, I'd want a
pattern-binder preprocessor (extending GHC is not as important to
me).
I see. though I'd hope that as long as we
Andres Loeh wrote:
The only reasons that I could see in favor of allowing empty
foralls is that it might be easier to automatically generate
code. Haskell seems to be a bit inconsistent in how it treats empty
constructs. For example, empty let and empty where seems to be
allowed, but not an
