# File lib/backports/1.8.7/enumerable/find_index.rb, line 6 def find_index(obj = Backports::Undefined) if obj != Backports::Undefined each_with_index do |element, i| return i if element == obj end elsif block_given? each_with_index do |element, i| return i if yield element end else return to_enum(:find_index) end nil end