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