# File lib/map.rb, line 59
    def conversion_methods
      @conversion_methods ||= (
        map_like = ancestors.select{|ancestor| ancestor <= Map}
        type_names = map_like.map do |ancestor|
          name = ancestor.name.to_s.strip
          next if name.empty?
          name.downcase.gsub(/::/, '_')
        end.compact
        list = type_names.map{|type_name| "to_#{ type_name }"}
        list.each{|method| define_conversion_method!(method)}
        list
      )
    end