class Rouge::Formatters::HTMLLineHighlighter

def stream(tokens)
  token_lines(tokens).with_index(1) do |line_tokens, lineno|
    line = %(#{@delegate.format(line_tokens)}\n)
    line = %(<span class="#{@highlight_line_class}">#{line}</span>) if @highlight_lines.include? lineno
    yield line
  end
end