You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: block_parser.rb
    path of file: ./repos/artichoke/artichoke-backend/vendor/ruby/lib/rdoc/rd
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
#
# DO NOT MODIFY!!!!
# This file is automatically generated by Racc 1.5.2
# from Racc grammar file "".
#

require 'racc/parser.rb'

class RDoc::RD

##
# RD format parser for headings, paragraphs, lists, verbatim sections that
# exist as blocks.

class BlockParser < Racc::Parser


# :stopdoc:

TMPFILE = ["rdtmp", $$, 0]

MARK_TO_LEVEL = {
  '='    => 1,
  '=='   => 2,
  '==='  => 3,
  '====' => 4,
  '+'    => 5,
  '++'   => 6,
}

# :startdoc:

##
# Footnotes for this document

attr_reader :footnotes

##
# Labels for items in this document

attr_reader :labels

##
# Path to find included files in

attr_accessor :include_path

##
# Creates a new RDoc::RD::BlockParser.  Use #parse to parse an rd-format
# document.

def initialize
  @inline_parser = RDoc::RD::InlineParser.new self
  @include_path = []

  # for testing
  @footnotes = []
  @labels    = {}
end

##
# Parses +src+ and returns an RDoc::Markup::Document.

def parse src
  @src = src
  @src.push false

  @footnotes = []
  @labels    = {}

  # @i: index(line no.) of src
  @i = 0

  # stack for current indentation
  @indent_stack = []

  # how indented.
  @current_indent = @indent_stack.join("")

  # RDoc::RD::BlockParser for tmp src
  @subparser = nil

  # which part is in now
  @in_part = nil
  @part_content = []

  @in_verbatim = false

  @yydebug = true

  document = do_parse

  unless @footnotes.empty? then
    blankline = document.parts.pop

    document.parts << RDoc::Markup::Rule.new(1)
    document.parts.concat @footnotes

    document.parts.push blankline
  end

  document
end

##
# Returns the next token from the document

def next_token # :nodoc:
  # preprocessing
  # if it is not in RD part
  # => method
  while @in_part != "rd"
    line = 
    
def parse src
  @src = src
  @src.push false

  @footnotes = []
  @labels    = {}

  # @i: index(line no.) of src
  @i = 0

  # stack for current indentation
  @indent_stack = []

  # how indented.
  @current_indent = @indent_stack.join("")

  # RDoc::RD::BlockParser for tmp src
  @subparser = nil

  # which part is in now
  @in_part = nil
  @part_content = []

  @in_verbatim = false

  @yydebug = true

  document = do_parse

  unless @footnotes.empty? then
    blankline = document.parts.pop

    document.parts << RDoc::Markup::Rule.new(1)
    document.parts.concat @footnotes

    document.parts.push blankline
  end

  document
end

##
# Returns the next token from the document

def next_token # :nodoc:
  # preprocessing
  # if it is not in RD part
  # => method
  while @in_part != "rd"
    line = @src[@i]
    @i += 1 # next line

    case line
    # src end
    when false
      return [false, false]
    # RD part begin
    when /^=begin\s*(?:\bRD\b.*)?\s*$/
      if @in_part # if in non-RD part
        @part_content.push(line)
      else
        @in_part = "rd"
        return [:WHITELINE, "=begin\n"] # <= for textblockand
      end
    # non-RD part begin
    when /^=begin\s+(\w+)/
      part = $1
      if @in_part # if in non-RD part
        @part_content.push(line)
      else
        @in_part = part if @tree.filter[part] # if filter exists
#  p "BEGIN_PART: #{@in_part}" # DEBUG
      end
    # non-RD part end
    when /^=end/
      if @in_part # if in non-RD part
#  p "END_PART: #{@in_part}" # DEBUG
        # make Part-in object
        part = RDoc::RD::Part.new(@part_content.join(""), @tree, "r")
        @part_content.clear
        # call filter, part_out is output(Part object)
        part_out = @tree.filter[@in_part].call(part)

        if @tree.filter[@in_part].mode == :rd # if output is RD formatted
          subtree = parse_subtree(part_out.to_a)
        else # if output is target formatted
          basename = TMPFILE.join('.')
          TMPFILE[-1] += 1
          tmpfile = open(@tree.tmp_dir + "/" + basename + ".#{@in_part}", "w")
          tmpfile.print(part_out)
          tmpfile.close
          subtree = parse_subtree(["=begin\n", "<<< #{basename}\n", "=end\n"])
        end