# File lib/html/pipeline/syntax_highlight_filter.rb, line 13
      def call
        doc.search('pre').each do |node|
          default = context[:highlight] && context[:highlight].to_s
          next unless lang = node['lang'] || default
          next unless lexer = lexer_for(lang)
          text = node.inner_text

          html = highlight_with_timeout_handling(text, lang)
          next if html.nil?

          node.inner_html = html
          klass = node['class']
          scope = context[:scope] || "highlight-#{lang}"
          klass = [klass, scope].compact.join ' '

          node['class'] = klass
        end
        doc
      end