# File lib/uri_template/rfc6570/expression/unnamed.rb, line 37
  def to_r_source
    vs = @variable_specs.size - 1
    i = 0
    source = regex_builder
    source.group do
      source.escaped_prefix
      @variable_specs.each do | var, expand , max_length |
        last = (vs == i)
        first = (i == 0)
        if expand
          source.group(true) do
            source.separated_list(first) do
              source.group do
                source.character_class('+').reluctant
                source.escaped_pair_connector
              end.length('?')
              source.character_class(max_length)
            end
          end
        else
          source.escaped_separator unless first
          source.group(true) do
            if last
              source.character_class_with_comma(max_length)
            else
              source.character_class(max_length)
            end
          end
        end
        i = i+1
      end
    end.length('?')
    return source.join
  end