--- /dev/null
+<?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);
+ }
+ }
+}