Hello I'm using ACL and I have trouble with REGEXP. I tried many ways but somehow it doesn't work.

The meta-field is a ACL-Textarea.

I need to search after searchword. After that word there may multiple whitespaces before there is either a comma, newline or end of string.

Here my code, please take a look at this line: $limiter = " *(\n|\,|$)";

...
          // Preparation
          $limiter = " *(\n|\,|$)";
          $search_names = explode(' ', $_POST['gsdname']);
...
          $search_language1 = '';
          if($_POST['workingLanguage1'])
          {
            $search_language1 = array(
              'key' => 'arbeitssprache',
              'value' => trim($_POST['workingLanguage1']).$limiter,
              'compare' => 'REGEXP'
            );
          }
...
          // Build search arguments
          $args = array(
            'post_type' => 'page',
            $parent_page_parameter => $parent_page_id,
            'title_filter' => $search_names,
            'meta_query' => array(
              'relation' => 'AND',
              $search_language1,
              $search_language2,
              $search_workingArea,
              $district_filter
            )
          );
          add_filter('posts_where', 'title_filter',10,2);
          $query = new WP_Query( $args );
          remove_filter('posts_where', 'title_filter',10);
...

Coma works fine, but the whitespace and end of string $ doesn't work. And I'm confused with whitespace since I expect to find something like "Search ," but it also find "SearchYaddaYadda,". Why? Whats wrong about " *"?

Best regards Floh