Regex does not work - Please help

[Anon]

Why ??? It checks nested parenteses

$variation="(( ( (?>[^()]+) | (?R) )* ))";

preg_match_all("%
                 \d \s*
                 $variation \s*
                 %Sxms",
                  "6 (in1a (in2) in1b)",
                  $out, PREG_SET_ORDER);
 echo "<pre>";
 print_r($out);
 echo "</pre>";

If I remove \d, it works fine

[tomhath]

You have a space after the first %, so its looking for a <blank>\d, at the beginning of the string, but there is no blank before the "6"

[rfurdzik]

According to the user guide (http://www.php.net/manual/en/pcre.pattern.modifiers.php) blank spaces should ignored:

x (PCRE_EXTENDED)
If this modifier is set, whitespace data characters in the pattern are totally ignored except when escaped or inside a character class, and characters between an unescaped # outside a character class and the next newline character, inclusive, are also ignored. This is equivalent to Perl's /x modifier, and makes it possible to include comments inside complicated patterns. Note, however, that this applies only to data characters. Whitespace characters may never appear within special character sequences in a pattern, for example within the sequence (?( which introduces a conditional subpattern.