On Thu, Feb 21, 2013 at 6:37 PM, Niko Matsakis <n...@alum.mit.edu> wrote: > There is some design work needed here. In general, this seems to be related > to the desire for associated types [2].
Coming from Haskell, they seem like separate things to me (or rather they're related only by them being extensions to the trait system). On the one hand there's the desire to have types/traits parameterized on things other than types: non-type template parameters in C++ parlance, or type-level literals in Haskell (or type-level things of kind other than * or k -> k, in a broader sense). And on the other hand there's the desire to have constants as members of a trait (type class). That's Haskell 98, no extensions required. E.g. you have `class Bounded a where minBound :: a; maxBound :: a`. (Haskell doesn't have a distinction between nullary functions and simple values, so there's no difference there between `static fn len() -> uint` and `const len: uint`.) But this is just a mapping from types to values, which is what type classes do. Associated types come into the picture when you want to map types to types. -- Your ship was destroyed in a monadic eruption. _______________________________________________ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
