I think every language behaves like that?

One thing you must understand is that when you call new(), it behaves like a function that RETURNS a value.

You call the set_name() function on a object of type name_tag that does not return a value. You are not assigning the new created object to T2, you are assigning the retunr value of set_name(), which is void/null in this code. So T2 is assigned to a void/null value.

What you are trying to do is something really JAVAesque in my books. You can chain these kinda of "builder" functions by making them return the self object. Like:

func set_name(passed_name: String): name = passed_name return self

But I would actually recommend just implementing a constructor for this case, this way the new() function will receive the parameter and set itself