Hindley-Milner type systems to the rescue! (With a sprinkling of Haskell style type classes.)
f :: Iterable a => a -> b
f x = (do stuff with x...)
f is defined to be constrained to accept only on types which implement the Iterable interface (however that's defined) as it's first argument and the compiler (or interpreter) will enforce that constraint.
You're implying that all type-systems derived from HM have a form of bounded polymorphism. They're not, for example OCaml does not have type classes (you could probably encode a lot into objects, though).
I don't think so: If you want the equivalent of Haskell type classes in OCaml then you have to either use a functors or some sort of class IIRC. I'm sure Oleg will have done something though.
yup, you're right, you got to use functors or go home.
Yeup, some folks did show the functors + modules \equiv type classes in some sense, for system F or a variant thereof. Theres also an oleg approach too I think.
