“_” parameter of Ruby block
问题 I met this when I read ZenTest source code: Here is the definition of add_mapping method: def add_mapping(regexp, &proc) @test_mappings << [regexp, proc] end In the Autottest.initailize() , add_method get called to add mapping for implementations. self.add_mapping(/^lib\/.*\.rb$/) do |filename, _| possible = File.basename(filename).gsub '_', '_?' files_matching %r%^test/.*#{possible}$% end My question is what "_", the second parameter of the block, means? Seems it is not used in the block.