block/HeadlineTrait.php
protected function identifyHeadline($line, $lines, $current)
	{
		return (
			// heading with #
			$line[0] === '#' && !preg_match('/^#\d+/', $line)
			||
			// underlined headline
			!empty($lines[$current + 1]) &&
			(($l = $lines[$current + 1][0]) === '=' || $l === '-') &&
			preg_match('/^(\-+|=+)\s*$/', $lines[$current + 1])
		);
	}
protected function identifyHeadline($line, $lines, $current)
	{
		return (
			// heading with #
			$line[0] === '#' && !preg_match('/^#\d+/', $line)
			||
			// underlined headline
			!empty($lines[$current + 1]) &&
			(($l = $lines[$current + 1][0]) === '=' || $l === '-') &&
			preg_match('/^(\-+|=+)\s*$/', $lines[$current + 1])
		);
	}
identify a line as a headline