public function skipUntil($regexp)
    {
        if ($this->scanUntil($regexp)) {
            return $this->head - $this->last;
        } else {
            return null;
        }
    }
public function skipUntil($regexp)
    {
        if ($this->scanUntil($regexp)) {
            return $this->head - $this->last;
        } else {
            return null;
        }
    }
public function skipUntil ( $ regexp ) { if ( $ this -> scanUntil ( $ regexp ) ) { return $ this -> head - $ this -> last ; } else { return null ; } }
Skips over the given regexp at or after the current position.

Returns the length of the string up to and including the end of the
match and advances the scanner’s position, or returns null if there
is no match.

@param string $regexp The regular expression to match.

@return int|null
Skips over the given regexp at or after the current position .