Symfony - Doctrine dql extension for from_unixtime()

FromUnixTImeFunction.php

<?php

namespace AppBundle\DQL;

use Doctrine\ORM\Query\Lexer;
use Doctrine\ORM\Query\AST\Functions\FunctionNode;

/**
 * FromUnixtimeFunction ::=
 *     "unix_timestamp" "(" ArithmeticPrimary "," ArithmeticPrimary ")"
 */

class FromUnixtimeFunction extends FunctionNode {

	public $firstDateExpression = null;
    public $secondDateExpression = null;

    public function parse(\Doctrine\ORM\Query\Parser $parser)
    {
        $parser->match(Lexer::T_IDENTIFIER);
        $parser->match(Lexer::T_OPEN_PARENTHESIS);
        $this->firstDateExpression = $parser->ArithmeticPrimary();
        $parser->match(Lexer::T_COMMA);
        $this->secondDateExpression = $parser->ArithmeticPrimary();
        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
    }

    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
    {
        return 'from_unixtime(' .
            $this->firstDateExpression->dispatch($sqlWalker) . ', ' .
            $this->secondDateExpression->dispatch($sqlWalker) .
        ')';
    }
}