rouge_linenos_patch.rb

def string_rsub(str, pattern, replacement)
  last_match = nil
  while true
    pos = last_match.nil? ? 0 : last_match.end(0)
    m = pattern.match(str, pos)
    break if m.nil?
      ast_match = m
  end
  last_match ? (last_match.pre_match + replacement + last_match.post_match) : str
end
def add_code_tag(code)
  # Add nested <code> tags to code blocks
  code = code.sub(/<pre>\n*/,'<pre><code class="language-' + @lang.to_s.gsub("+", "-") + '" data-lang="' + @lang.to_s + '">')
  code = string_rsub(code, /\n*<\/pre>/,"</code></pre>")
  code.strip
end