'Initialise with the argument syntax tree and parser function.'

def __init__(self, stack, fn_name, raw_args, parse_func, template):

    super(Macro, self).__init__(stack, fn_name, raw_args)
    self._tmplref = (weakref.ref(template) if (template is not None) else None)
    self.parsed = self.parse_args(parse_func)
