    # File lib/facets/yore/builderobject.rb, line 141
      def method_missing(o, *a, &b)
        o = o.to_s

        if b
          @stack << @out
          @out = ''
          @instance_eval.call(&b)
          s = @out
          @out = @stack.pop
          a.unshift(s)
        end

        if o[0,1] == '_'
          m = o[1..-1].to_sym
          @out << @module.send(m, *a, &b).to_s
        else
          o = o.chomp('!') if o[-1,1] == '!'
          @out << @module.send(@constructor, o, *a).to_s
        end
      end