pushBlockStack example

    public function parse(Token $token): Node
    {
        $lineno = $token->getLine();
        $stream = $this->parser->getStream();
        $name = $stream->expect(/* Token::NAME_TYPE */ 5)->getValue();
        if ($this->parser->hasBlock($name)) {
            throw new SyntaxError(sprintf("The block '%s' has already been defined line %d.", $name, $this->parser->getBlock($name)->getTemplateLine()), $stream->getCurrent()->getLine(), $stream->getSourceContext());
        }
        $this->parser->setBlock($name, $block = new BlockNode($name, new Node([]), $lineno));
        $this->parser->pushLocalScope();
        $this->parser->pushBlockStack($name);

        if ($stream->nextIf(/* Token::BLOCK_END_TYPE */ 3)) {
            $body = $this->parser->subparse([$this, 'decideBlockEnd'], true);
            if ($token = $stream->nextIf(/* Token::NAME_TYPE */ 5)) {
                $value = $token->getValue();

                if ($value != $name) {
                    throw new SyntaxError(sprintf('Expected endblock for block "%s" (but "%s" given).', $name, $value), $stream->getCurrent()->getLine(), $stream->getSourceContext());
                }
            }
        } else {