parse_method_or_yield_parameters

# File lib/rdoc/parser/ruby.rb, line 2214
  def parse_method_or_yield_parameters(method = nil,
                                       modifiers = RDoc::METHOD_MODIFIERS)
    skip_tkspace(false)
    tk = get_tk

    # Little hack going on here. In the statement
    #  f = 2*(1+yield)
    # We see the RPAREN as the next token, so we need
    # to exit early. This still won't catch all cases
    # (such as "a = yield + 1"
    end_token = case tk
                when TkLPAREN, TkfLPAREN
                  TkRPAREN
                when TkRPAREN
                  return ""
                else
                  TkNL
                end
    nest = 0

    loop do
        case tk
        when TkSEMICOLON
          break
        when TkLBRACE
          nest += 1
        when TkRBRACE
          # we might have a.each {|i| yield i }
          unget_tk(tk) if nest.zero?
          nest -= 1
          break if nest <= 0
        when TkLPAREN, TkfLPAREN
          nest += 1
        when end_token
          if end_token == TkRPAREN
            nest -= 1
            break if @scanner.lex_state == EXPR_END and nest <= 0
          else
            break unless @scanner.continue
          end
        when method && method.block_params.nil? && TkCOMMENT
          unget_tk(tk)
          read_documentation_modifiers(method, modifiers)
        end
      tk = get_tk
    end
    res = get_tkread.tr("\n", " ").strip
    res = "" if res == ";"
    res
  end