blob: a72bc4fc65443e56a3b2c2e5ea5b0beb9b6379af [file] [log] [blame]
Matthias Andreas Benkard12a57352021-12-28 18:02:04 +01001<?php
2
3/*
4 * This file is part of Twig.
5 *
6 * (c) Fabien Potencier
7 *
8 * For the full copyright and license information, please view the LICENSE
9 * file that was distributed with this source code.
10 */
11
12namespace Twig\Node\Expression;
13
14use Twig\Compiler;
15use Twig\Node\Expression\Binary\AndBinary;
16use Twig\Node\Expression\Test\DefinedTest;
17use Twig\Node\Expression\Test\NullTest;
18use Twig\Node\Expression\Unary\NotUnary;
19use Twig\Node\Node;
20
21class NullCoalesceExpression extends ConditionalExpression
22{
23 public function __construct(Node $left, Node $right, int $lineno)
24 {
25 $test = new DefinedTest(clone $left, 'defined', new Node(), $left->getTemplateLine());
26 // for "block()", we don't need the null test as the return value is always a string
27 if (!$left instanceof BlockReferenceExpression) {
28 $test = new AndBinary(
29 $test,
30 new NotUnary(new NullTest($left, 'null', new Node(), $left->getTemplateLine()), $left->getTemplateLine()),
31 $left->getTemplateLine()
32 );
33 }
34
35 parent::__construct($test, $left, $right, $lineno);
36 }
37
38 public function compile(Compiler $compiler): void
39 {
40 /*
41 * This optimizes only one case. PHP 7 also supports more complex expressions
42 * that can return null. So, for instance, if log is defined, log("foo") ?? "..." works,
43 * but log($a["foo"]) ?? "..." does not if $a["foo"] is not defined. More advanced
44 * cases might be implemented as an optimizer node visitor, but has not been done
45 * as benefits are probably not worth the added complexity.
46 */
47 if ($this->getNode('expr2') instanceof NameExpression) {
48 $this->getNode('expr2')->setAttribute('always_defined', true);
49 $compiler
50 ->raw('((')
51 ->subcompile($this->getNode('expr2'))
52 ->raw(') ?? (')
53 ->subcompile($this->getNode('expr3'))
54 ->raw('))')
55 ;
56 } else {
57 parent::compile($compiler);
58 }
59 }
60}