@
(?(DEFINE)
(?<next_open_tag>
[^<]*+
(?i: <++[^<?s][^<]*
| <++(?! \?php
| \?=
| script\s*language\s*=\s*([\'"]?)php\g{-1}\s*>
) [^<]*
)*+
(?i: <++(?: \?php
| \?=
| [^>]+
)
| \z
)
)
)
\A (?&next_open_tag) \K
|
[^'"`/#<?]*+
(?: '(?:[^'\\]+|\\.)*+' [^\'"`/#<?]*
| "(?:[^"\\]+|\\.)*+" [^\'"`/#<?]*
| `(?:[^`\\]+|\\.)*+` [^\'"`/#<?]*
| /(?![/*]) [^\'"`/#<?]* # stop for // or /*
| # if close tag ?>
\? (?: >(?&next_open_tag)[^\'"`/#<?]* | )
| < (?: # heredoc or nowdoc
<<[\ \t]*([\'"]?)
([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)
\g{-2}[\ \t]*[\r\n]
(?-s:.*+[\r\n])*?
\g{-1}[\r\n;]
[^\'"`/#<?]*