rust-lang/rfcs — pull request #216 by Gankro (2014-08-28 20:56:53+00:00)
Title: Collection Views

Add additional iterator-like View objects to collections.

Views provide a composable mechanism for in-place observation and mutation of a single element in the collection, without having to "re-find" the element multiple times. This deprecates several "internal mutation" methods like hashmap's `find_or_insert_with`.