Description:
------------
Including (?P&name) in a pattern (as described on http://www.php.net/manual/en/regexp.reference.recursive.php) causes an error. Changing it to (?P>name) or (?&name) works as expected (see http://perldoc.perl.org/perlre.html#PCRE%2fPython-Support and elsewhere on the same page). The reference to (?P&name) needs to be changed to (?&name).

Test script:
---------------
<?php
var_export(preg_match('/(?<foo>a)(?P>foo)/', 'aa')); // Good
print("\n");
var_export(preg_match('/(?<foo>a)(?&foo)/', 'aa')); // Good
print("\n");
var_export(preg_match('/(?<foo>a)(?P&foo)/', 'aa')); // Bad
?>


Actual result:
--------------
1
1
Warning:  preg_match(): Compilation failed: unrecognized character after (?P at offset ...