SandboxNode example

foreach ($body as $node) {
                if ($node instanceof TextNode && ctype_space($node->getAttribute('data'))) {
                    continue;
                }

                if (!$node instanceof IncludeNode) {
                    throw new SyntaxError('Only "include" tags are allowed within a "sandbox" section.', $node->getTemplateLine(), $stream->getSourceContext());
                }
            }
        }

        return new SandboxNode($body, $token->getLine(), $this->getTag());
    }

    public function decideBlockEnd(Token $token): bool
    {
        return $token->test('endsandbox');
    }

    public function getTag(): string
    {
        return 'sandbox';
    }
}