gistfile1.rb

    # Instant result methods w/block (and different arities)
    [ [ %w[partition group_by sort_by min_by max_by minmax_by
        any? one? all? none?], ""],
      [ %w[each_slice each_cons each_with_object], "arg" ],
      [ %w[each_with_index reverse_each each_entry find
        detect find_index], "*args"] ].each do |methods, arguments|

      methods.each do |method|
        class_eval <<-METHOD_DEF
          def #{method} #{arguments}
            block_given? ? super : to_lazy_enum(:#{method})
          end
        METHOD_DEF
      end
    end