Re: Regex for balanced brackets?

Jeffrey Sambells wrote:

I came across this method of matching brackets with regex in .NET http://puzzleware.net/blogs/archive/2005/08/13/22.aspx but I am wondering if it is possible to do the same in PHP? I've tried it a bit but I can't seem to get it to work properly. I'm just wondering if I am doing something wrong or if it is just not possible. Thanks. here is the code I was playing with: <?php $pattern = <<<PATTERN \{

    (?>
        [^{}]+
        |
        \{ (?P<DEPTH>)
        |
        \} (?P<-DEPTH>)
    )*
    (?(DEPTH)(?!))

\} PATTERN; $subject = <<<SUBJECT test {

    test2 {
        test3
    }

} test4 { } SUBJECT; preg_match_all("/$pattern/ix",$subject,$matches); header("content-type: text/plain; "); var_dump($matches); ?> - Jeff ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Jeffrey Sambells Director of Research and Development Zend Certified Engineer (ZCE) We-Create Inc. jeff@wecreate.com email 519.745.7374 office 519.897.2552 mobile ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Get Mozilla Firefox at http://spreadfirefox.com

If I'm understanding what you want, consider this. I use it to check matching tags. First get an array of all the start tags: $pattern= "%<([^/][a-z_\-]*)>%i"; //all start tags used <xxx> preg_match_all("$pattern", $text_str, $matches); $start_tags= $matches[1]; $start_tag_nums= array_count_values($start_tags); //get count for each tag Then do the same for your end tags, using the same pattern but with the end tag slash. </.... Finally, you make a text list of the mismatches: foreach($start_tag_nums as $tag=> $num){ if($num != $end_tag_nums[$tag]) $end_error_msg .= "&lt;$tag&gt; || "; }//end foreach echo $end_error_msg;