D-Programming-Language/druntime — pull request #574 by quickfur (2013-08-15 19:22:50+00:00)
Title: Implement AA .byPair forward range

Fixes issue 9119.

This pull also adds forward range capability to byKey and byValue, since byPair already provides that functionality. Exporting a forward range API makes AA's usable with many more Phobos algorithms, and costs almost nothing.