| <?php |
| |
| /* |
| * This file is part of Twig. |
| * |
| * (c) Fabien Potencier |
| * |
| * For the full copyright and license information, please view the LICENSE |
| * file that was distributed with this source code. |
| */ |
| |
| namespace Twig\Node\Expression; |
| |
| use Twig\Compiler; |
| use Twig\Node\Expression\Binary\AndBinary; |
| use Twig\Node\Expression\Test\DefinedTest; |
| use Twig\Node\Expression\Test\NullTest; |
| use Twig\Node\Expression\Unary\NotUnary; |
| use Twig\Node\Node; |
| |
| class NullCoalesceExpression extends ConditionalExpression |
| { |
| public function __construct(Node $left, Node $right, int $lineno) |
| { |
| $test = new DefinedTest(clone $left, 'defined', new Node(), $left->getTemplateLine()); |
| // for "block()", we don't need the null test as the return value is always a string |
| if (!$left instanceof BlockReferenceExpression) { |
| $test = new AndBinary( |
| $test, |
| new NotUnary(new NullTest($left, 'null', new Node(), $left->getTemplateLine()), $left->getTemplateLine()), |
| $left->getTemplateLine() |
| ); |
| } |
| |
| parent::__construct($test, $left, $right, $lineno); |
| } |
| |
| public function compile(Compiler $compiler): void |
| { |
| /* |
| * This optimizes only one case. PHP 7 also supports more complex expressions |
| * that can return null. So, for instance, if log is defined, log("foo") ?? "..." works, |
| * but log($a["foo"]) ?? "..." does not if $a["foo"] is not defined. More advanced |
| * cases might be implemented as an optimizer node visitor, but has not been done |
| * as benefits are probably not worth the added complexity. |
| */ |
| if ($this->getNode('expr2') instanceof NameExpression) { |
| $this->getNode('expr2')->setAttribute('always_defined', true); |
| $compiler |
| ->raw('((') |
| ->subcompile($this->getNode('expr2')) |
| ->raw(') ?? (') |
| ->subcompile($this->getNode('expr3')) |
| ->raw('))') |
| ; |
| } else { |
| parent::compile($compiler); |
| } |
| } |
| } |