Negative indexing on slice

[gaffney2010]

Have you thought about adding functionality for Python-style negative indices on the slice function?

[ryanhaining]

Yeah, I would also like to be able to use that, but it's pretty complicated to implement. Everything in iter::slice needs to work with types that don't support std::prev / operator--, so there would be some wacky complie-time conditional work. The best I could say for now would be to use iter::slice + iter::reversed, unless you can point to a case where that doesn't get what you want?