src/Parser/Parser.php
protected function parseExpression($s, Node $statement, array $filters): Root
    {
        foreach ($filters as list (, $filter)) {
            $statement = new Filter($statement, $filter[0], $filter[1]);
        }
        
        return new Root($statement);
    }
protected function parseExpression($s, Node $statement, array $filters): Root
    {
        foreach ($filters as list (, $filter)) {
            $statement = new Filter($statement, $filter[0], $filter[1]);
        }
        
        return new Root($statement);
    }
Expression ::= T_DELIM_START Statement ( '|' Filter )* T_DELIM_END