public function isDelimiter()
    {
        for ($i = count($this->tokens) - 1; $i >= 0; $i--) {
            $t = $this->tokens[$i];
            if ($t[0] === null || $t[0] === 'COMMENT') {
                continue;
            } elseif ($t[0] === 'OPENER' || $t[0] === 'OPERATOR') {
                return true;
            } elseif ($t[0] === 'IDENT') {
                switch ($t[1]) {
                    // named operators
                    case 'lt':
                    case 'gt':
                    case 'le':
                    case 'ge':
                    case 'eq':
                    case 'ne':
                    case 'cmp':
                    case 'and':
                    case 'or':
                    case 'xor':
                    // other keywords/functions
                    case 'if':
                    case 'elsif':
                    case 'while':
                    case 'unless':
                    case 'split':
                    case 'print':
                        return true;
                }
            }
            return false;
        }
        return true;
    }