Ryan Ingram wrote:
Heinrich wrote:
While I do agree that qualified names are annoying at times, I think that type directed name disambiguation is a Pandora's box.
I see where you are going, but I'm not sure I agree. Let me give an example from another language with this kind of resolution: C++. From a purely practical point of view, function overloading in C++ does what I want almost all the time. And when it doesn't do what I want, it's always been immediately obvious, and it's a sign that my design is flawed.
But those cases where it does what I want have been incredibly useful.
Sure, overloading is useful. But to avoid headache in a polymorphic language, I'd prefer a principled approach to it. Hence, I'm convinced that there should be only one mechanism for overloading in Haskell; which is type classes at the moment. It appears that type direction name disambiguation can be implemented with (automatically generated) type classes? Something like this class Function_lookup t where lookup :: t instance Function_lookup (k -> [(k,a)] -> Maybe a) where lookup = ... instance Function_lookup (k -> Map k a -> Maybe a) where lookup = ... For each ambiguous function, the compiler creates a type class and corresponding instances and type inference will sort out the rest (or throw a type error). Regards, apfelmus -- http://apfelmus.nfshost.com