# File lib/asciidoctor/substituters.rb, line 802
  def highlight_source(source)
    Helpers.require_library 'coderay'
    ::CodeRay::Duo[attr('language', 'text').to_sym, :html, {
        :css => @document.attributes.fetch('coderay-css', 'class').to_sym,
        :line_numbers => (attr?('linenums') ? @document.attributes.fetch('coderay-linenums-mode', 'table').to_sym : nil),
        :line_number_anchors => false}].highlight(source).chomp
  end