> On 10 Apr 2014, at 00:22, Kevin Ballard <ke...@sb.org> wrote: > > FWIW, my point about range is it relies on One being the number 1, rather > than being the multiplicative identity. AFAIK there's nothing special about 1 > in a ring outside of its status as a multiplicative identity. Certainly it's > not considered some special value for addition.
Another problem with std::iter::range is that it requires too much from its argument type A by saying A must implement Add<A, A> while it only returns a forward iterator. Perhaps, in order to make a more sensible implementation of iter::range, a new concept, a trait, is needed to be able to specify that a certain type T implements a method 'increment' that modifies a variable of type T from value x to value y such that: 1) x < y 2) there is no valid value z of type T satisfying x < z < y For integral types there would an implementation of this trait in stdlib with 'increment' doing x += 1; Then, a natural extension to this trait would be a trait that has a method 'advance(n: uint)' that would, at constant time, conceptually call the 'increment' method n times. Then there would also be a 'decrement' method for going the other direction. There probably needs to be some other use cases for this new trait to carry its weight though. _______________________________________________ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
