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vichan/inc/lib/Twig/Node/Expression/NullCoalesce.php
2018-05-10 18:25:37 +08:00

49 lines
1.9 KiB
PHP

<?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.
*/
class Twig_Node_Expression_NullCoalesce extends Twig_Node_Expression_Conditional
{
public function __construct(Twig_NodeInterface $left, Twig_NodeInterface $right, $lineno)
{
$test = new Twig_Node_Expression_Binary_And(
new Twig_Node_Expression_Test_Defined(clone $left, 'defined', new Twig_Node(), $left->getTemplateLine()),
new Twig_Node_Expression_Unary_Not(new Twig_Node_Expression_Test_Null($left, 'null', new Twig_Node(), $left->getTemplateLine()), $left->getTemplateLine()),
$left->getTemplateLine()
);
parent::__construct($test, $left, $right, $lineno);
}
public function compile(Twig_Compiler $compiler)
{
/*
* This optimizes only one case. PHP 7 also supports more complex expressions
* that can return null. So, for instance, if log is defined, log("foo") ?? "..." works,
* but log($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 (PHP_VERSION_ID >= 70000 && $this->getNode('expr2') instanceof Twig_Node_Expression_Name) {
$this->getNode('expr2')->setAttribute('always_defined', true);
$compiler
->raw('((')
->subcompile($this->getNode('expr2'))
->raw(') ?? (')
->subcompile($this->getNode('expr3'))
->raw('))')
;
} else {
parent::compile($compiler);
}
}
}
class_alias('Twig_Node_Expression_NullCoalesce', 'Twig\Node\Expression\NullCoalesceExpression', false);