rspec/rspec-core — pull request #1738 by myronmarston (2014-10-10 06:51:16+00:00)
Title: Allocation optimization

This is my first stab at #1167.

I found some low-hanging fruit we can optimize. One change cuts string allocations when defining examples by ~70%. Another cuts string allocations when running examples by ~50%.

Note that some of the improvements here will only be noticeable on 2.1+; I used the new `.freeze` thing on string literals to get certain static strings to be re-usable. We can consider extracting constants for them, which will benefit other versions, but I don't really want to go down that path as a general approach (although we may in some cases). I think it's OK for some optimizations to just help 2.1+ since that's the future of ruby.