parse_method_or_yield_parameters

# File lib/rdoc/parser/ruby.rb, line 1131
  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 then
        break if nest == 0
      when TkLBRACE, TkfLBRACE then
        nest += 1
      when TkRBRACE then
        nest -= 1
        if nest <= 0
          # we might have a.each { |i| yield i }
          unget_tk(tk) if nest < 0
          break
        end
      when TkLPAREN, TkfLPAREN then
        nest += 1
      when end_token then
        if end_token == TkRPAREN
          nest -= 1
          break if @scanner.lex_state == EXPR_END and nest <= 0
        else
          break unless @scanner.continue
        end
      when TkRPAREN then
        nest -= 1
      when method && method.block_params.nil? && TkCOMMENT then
        unget_tk tk
        read_documentation_modifiers method, modifiers
        @read.pop
      when TkCOMMENT then
        @read.pop
      when nil then
        break
      end
      tk = get_tk
    end

    res = get_tkread.gsub(/\s+/, ' ').strip
    res = '' if res == ';'
    res
  end