class RDoc::Markup::ToBs

def accept_heading heading
  use_prefix or @res << ' ' * @indent
  @res << @headings[heading.level][0]
  @in_b = true
  @res << attributes(heading.text)
  @in_b = false
  @res << @headings[heading.level][1]
  @res << "\n"
end

def annotate tag
  case tag
  when '+b' then @in_b = true
  when '-b' then @in_b = false
  when '+_' then @in_em = true
  when '-_' then @in_em = false
  end
  ''
end

def convert_special special
  convert_string super
end

def convert_string string
  return string unless string.respond_to? :chars # your ruby is lame
  return string unless @in_b or @in_em
  chars = if @in_b then
            string.chars.map do |char| "#{char}\b#{char}" end
          elsif @in_em then
            string.chars.map do |char| "_\b#{char}" end
          end
  chars.join
end

def init_tags
  add_tag :BOLD, '+b', '-b'
  add_tag :EM,   '+_', '-_'
  add_tag :TT,   ''  , ''   # we need in_tt information maintained
end

def initialize markup = nil
  super
  @in_b  = false
  @in_em = false
end