# File lib/asciidoctor/parser.rb, line 1640
  def self.atx_section_title? line
    if Compliance.markdown_syntax ? ((line.start_with? '=', '#') && ExtAtxSectionTitleRx =~ line) :
        ((line.start_with? '=') && AtxSectionTitleRx =~ line)
      $1.length - 1
    end
  end