http://rspec.info/documentation/3.8/rspec-core/RSpec/Core/Example/Procsy.html  http://rspec.info/documentation/3.9/rspec-core/RSpec/Core/Example/Procsy.html   The same on the other doc pages:  Same on 3.7 and 3.8, didn't look further.