XML tag regular expression

xml_tag_regex.php

$re = '/(<\s*(\w+)((?:\s+\w+(?:\s*=\s*(?:(?:"(?<=")(?:(?<=\\\\)"|[^"])*(?=")")|(?:\'(?<=\')(?:(?<=\\\\)\'|[^\'])*(?=\')\')))?)*)\s*>((?<=\>)(?:[^<>])*(?=\<))((?1))*((?<=\>)(?:[^<>])*(?=\<))<\s*\/\2\s*>)/i';
$str = '<a class="foo" style="bar: \'a\'; baz: \\"bax\\""> front
 <b class="i"> inner <d attr= \'bak\\\'\\\'\'></d></b>
last
</a>';

preg_match_all($re, $str, $matches);

// Print the entire match result
print_r($matches);