“IMO it's pointless to distinguish syntactically between iterating forwards and backwards” — I completely agree. It’s really a compiler-macro limitation that’s preventing me from doing this.. though I don’t have to go that route.

I think what you’re suggesting would require the <a, b> syntax to produce a proper iterator type, which it doesn’t currently do. That’s definitely worth considering — then you could attach methods, etc.

Thanks for the suggestion! I’ll think about the best way to fix this..