how-to-use-module-eval-so-it-reports-line-numbers.rb

        module_eval(<<-__, __FILE__, __LINE__ - 1)

          def #{ mode }(*args, &block)
            if args.empty?
              mode(#{ mode.inspect }, &block)
            else
              mode(#{ mode.inspect }) do
                call(*args, &block)
              end
            end
          end

          def #{ mode }?(&block)
            mode?(#{ mode.inspect }, &block)
          end

        __