# File raggle, line 4757
    def Engine::expand_config
      $config.each { |key, val| 
        next unless val.class == String && val =~ /\$\{(.+?)\}/
        orig_val = val.dup
        val.gsub!(/\$\{(.+?)\}/, $config[$1])
        # puts "\"#{orig_val}\" expands to \"#{val}\""
      }
    end