getNodeVisitors example

    public function testEmptyExtensions(): void
    {
        $extension = new NodeExtension(
            $this->createMock(TemplateFinder::class),
            $this->createMock(TemplateScopeDetector::class),
        );

        static::assertEmpty($extension->getFunctions());
        static::assertEmpty($extension->getFilters());
        static::assertEmpty($extension->getNodeVisitors());
        static::assertEmpty($extension->getOperators());
        static::assertEmpty($extension->getTests());
    }
}

        $this->extensionSet->addNodeVisitor($visitor);
    }

    /** * @return NodeVisitorInterface[] * * @internal */
    public function getNodeVisitors(): array
    {
        return $this->extensionSet->getNodeVisitors();
    }

    public function addFilter(TwigFilter $filter)
    {
        $this->extensionSet->addFilter($filter);
    }

    /** * @internal */
    public function getFilter(string $name): ?TwigFilter
    {

// token parsers         foreach ($extension->getTokenParsers() as $parser) {
            if (!$parser instanceof TokenParserInterface) {
                throw new \LogicException('getTokenParsers() must return an array of \Twig\TokenParser\TokenParserInterface.');
            }

            $this->parsers[$parser->getTag()] = $parser;
        }

        // node visitors         foreach ($extension->getNodeVisitors() as $visitor) {
            $this->visitors[] = $visitor;
        }

        // operators         if ($operators = $extension->getOperators()) {
            if (!\is_array($operators)) {
                throw new \InvalidArgumentException(sprintf('"%s::getOperators()" must return an array with operators, got "%s".', \get_class($extension), \is_object($operators) ? \get_class($operators) : \gettype($operators).(\is_resource($operators) ? '' : '#'.$operators)));
            }

            if (2 !== \count($operators)) {
                throw new \InvalidArgumentException(sprintf('"%s::getOperators()" must return an array of 2 elements, got %d.', \get_class($extension), \count($operators)));
            }

return sprintf('__internal_parse_%d', $this->varNameSalt++);
    }

    public function parse(TokenStream $stream, $test = null, bool $dropNeedle = false): ModuleNode
    {
        $vars = get_object_vars($this);
        unset($vars['stack'], $vars['env'], $vars['handlers'], $vars['visitors'], $vars['expressionParser'], $vars['reservedMacroNames'], $vars['varNameSalt']);
        $this->stack[] = $vars;

        // node visitors         if (null === $this->visitors) {
            $this->visitors = $this->env->getNodeVisitors();
        }

        if (null === $this->expressionParser) {
            $this->expressionParser = new ExpressionParser($this, $this->env);
        }

        $this->stream = $stream;
        $this->parent = null;
        $this->blocks = [];
        $this->macros = [];
        $this->traits = [];