DX: Add a DQL AGE function to calculate age between two dates

src/Bundle/ChillMainBundle/Doctrine/DQL/Age.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Chill\MainBundle\Doctrine\DQL;
+
+use Doctrine\ORM\Query\AST\Functions\FunctionNode;
+use Doctrine\ORM\Query\Lexer;
+use Doctrine\ORM\Query\Parser;
+use Doctrine\ORM\Query\SqlWalker;
+
+class Age extends FunctionNode
+{
+    private $value1;
+
+    private $value2;
+
+    public function getSql(SqlWalker $sqlWalker)
+    {
+        if (null !== $this->value2) {
+            return sprintf(
+                'AGE(%s, %s)',
+                $this->value1->dispatch($sqlWalker),
+                $this->value2->dispatch($sqlWalker)
+            );
+        }
+
+        return sprintf(
+            'AGE(%s)',
+            $this->value1->dispatch($sqlWalker),
+        );
+    }
+
+    public function parse(Parser $parser)
+    {
+        $parser->match(Lexer::T_IDENTIFIER);
+        $parser->match(Lexer::T_OPEN_PARENTHESIS);
+
+        $this->value1 = $parser->SimpleArithmeticExpression();
+
+        $parser->match(Lexer::T_COMMA);
+
+        $this->value2 = $parser->SimpleArithmeticExpression();
+
+        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
+    }
+}