class Kramdown::Parser::Kramdown

def parse_link
  start_line_number = @src.current_line_number
  result = @src.scan(LINK_START)
  cur_pos = @src.pos
  saved_pos = @src.save_pos
  link_type = (result =~ /^!/ ? :img : :a)
  # no nested links allowed
  if link_type == :a && (@tree.type == :img || @tree.type == :a || @stack.any? {|t,s| t && (t.type == :img || t.type == :a)})
    add_text(result)
    return
  end
  el = Element.new(link_type, nil, nil, :location => start_line_number)
  count = 1
  found = parse_spans(el, LINK_BRACKET_STOP_RE) do
    count = count + (@src[1] ? -1 : 1)
    count - el.children.select {|c| c.type == :img}.size == 0
  end
  unless found
    @src.revert_pos(saved_pos)
    add_text(result)
    return
  end
  alt_text = extract_string(cur_pos...@src.pos, @src).gsub(ESCAPED_CHARS, '\1')
  @src.scan(LINK_BRACKET_STOP_RE)
  # reference style link or no link url
  if @src.scan(LINK_INLINE_ID_RE) || !@src.check(/\(/)
    link_id = normalize_link_id(@src[1] || alt_text)
    if @link_defs.has_key?(link_id)
      add_link(el, @link_defs[link_id][0], @link_defs[link_id][1], alt_text,
               @link_defs[link_id][2] && @link_defs[link_id][2].options[:ial])
    else
      warning("No link definition for link ID '#{link_id}' found on line #{start_line_number}")
      @src.revert_pos(saved_pos)
      add_text(result)
    end
    return
  end
  # link url in parentheses
  if @src.scan(/\(<(.*?)>/)
    link_url = @src[1]
    if @src.scan(/\)/)
      add_link(el, link_url, nil, alt_text)
      return
    end
  else
    link_url = ''
    nr_of_brackets = 0
    while temp = @src.scan_until(LINK_PAREN_STOP_RE)
      link_url << temp
      if @src[2]
        nr_of_brackets -= 1
        break if nr_of_brackets == 0
      elsif @src[1]
        nr_of_brackets += 1
      else
        break
      end
    end
    link_url = link_url[1..-2]
    link_url.strip!
    if nr_of_brackets == 0
      add_link(el, link_url, nil, alt_text)
      return
    end
  end
  if @src.scan(LINK_INLINE_TITLE_RE)
    add_link(el, link_url, @src[2], alt_text)
  else
    @src.revert_pos(saved_pos)
    add_text(result)
  end
end