note 125521 added to regexp.reference.recursive

This regexp can be used for parsing IF conditions. $str = ' (IF_MYVAR)My var is printed (OR_MYVARTWO)My var two is printed (OR_ANOTHER)if you use OR you don't have to END everytime (ELSE)Whatever bro(END) (IF_BLUE)Something (IF_SUPERB)super(END) blue - this is simple IF condition(END) '; function isCondition($k) { // put your user conditions here $conds = []; $conds['BLUE'] = true; $conds['MYVARTWO'] = true; $conds['ELSE'] = true; // always true return $conds[$k]; } function findConditions($str) { $pattern = '~ \(if_([^\)]+)\) ((?: (?!\((end|if_)). | (?R) )*+) \(end\) ~xis'; $str = preg_replace_callback($pattern, function($m) { $k = $m[1]; $v = $m[2]; $v = findConditions($v) ?: $v; $ors = preg_split('~(?=\((OR_[^\)]+|ELSE))~is', $v); $v = array_shift($ors); // hlavní if (isCondition($k)) return findConditions($v); else { foreach ($ors as $or) { list($k, $v) = explode(")", $or, 2); $k = substr($k, 1); if (isCondition($k)) return findConditions($v); } } return ''; // no matching condition }, $str); return $str; }; // will output: Whatever bro \n\n Something blue echo findConditions($str); ---- Server IP: 45.112.84.4 Probable Submitter: 185.85.3.174 (proxied: 85.135.47.154) ---- Manual Page -- http://php.net/manual/en/regexp.reference.recursive.php Edit -- https://master.php.net/note/edit/125521 Del: integrated -- https://master.php.net/note/delete/125521/integrated Del: useless -- https://master.php.net/note/delete/125521/useless Del: bad code -- https://master.php.net/note/delete/125521/bad+code Del: spam -- https://master.php.net/note/delete/125521/spam Del: non-english -- https://master.php.net/note/delete/125521/non-english Del: in docs -- https://master.php.net/note/delete/125521/in+docs Del: other reasons-- https://master.php.net/note/delete/125521 Reject -- https://master.php.net/note/reject/125521 Search -- https://master.php.net/manage/user-notes.php