On Thu, Jul 23, 2009 at 9:01 PM, wren ng thornton<[email protected]> wrote: > John Lask wrote: >> >> Can anyone explain the theoretical reason for this limitation, ie other >> than it is a syntactical restriction, what would it take to lift this >> restriction ? > > There are a couple of theoretical concerns, mainly that full type-level > lambdas can lead down a rocky path (though simple combinators like `flip` > and `const` are fine, and that's all we'd need for most cases). But by and > large it's just a syntactic restriction.
I wouldn't say it's "just" a syntactic restriction. I'm pretty sure unrestricted type lambdas are incompatible with Haskell's class system. Otherwise, you might end up with Functor instances for /\b. (a,b) and /\a. (a,b), at which point fmap (+1) (1,2) is ambiguous. -- Dave Menendez <[email protected]> <http://www.eyrie.org/~zednenem/> _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
