array of required twig variables in symfony

Question

If there any way to discover the variables required from a Twig template? Example, if I had:

Hello {{ user }}! You're {{ age }} years old, well done big man!

I'd be able to load this template and then gather each of the required variables, eventually allowing me to have something like:

Array ( [0] => user [1] => age )

The end goal of this is to be able to define a view and then have the system create a form based on the required variables in a template file.

Answer 1

Working Solution

Thanks to morg for pointing me towards tokenize I was able to get what I wanted using the following (I placed it in my controller for testing):

$lexer = new \Twig_Lexer(new \Twig_Environment());
$stream = $lexer->tokenize(new \Twig_Source('{{test|raw}}{{test2|raw|asd}}{{another}}{{help_me}}', null));
$variables = array();
while (!$stream->isEOF()) {
    $token = $stream->next();
    if($token->getType() === \Twig_Token::NAME_TYPE){
        $variables[] = $token->getValue();
        while (!$stream->isEOF() && $token->getType() !== \Twig_Token::VAR_END_TYPE) {
            $token = $stream->next();
        }
    }
}
$variables = array_unique($variables);

This returns:

Array
(
    [0] => test
    [1] => test2
    [2] => another
    [3] => help_me
)

You'll notice I only get variables and not any of the functions (this is through design), although you could remove the nested while loop if you wish to get both variables and functions.