> The more I look at it, the more I'm convinced that we really need to add a primitive to forward ranges that returns the first n elements of that range. Without that, I don't see how you can get a range of the correct type with only those elements in it unless it's also a bidirectional range, which some ranges (like SList's range) aren't.
Huh, yeah I think I agree. It seems like ranges are just delayed evaluation, and that, at some point, we need to be able to force their evaluation -- otherwise, it's like combining Scheme's (delay X) and (force Y) operations with mutation, which just doesn't work sensibly in non-functional programming.
