4 ms·

Again i'm missing the problem. If typecheck.static_type evaluates type on an object , typecheck.static_type(foo) returns type 'function'. And our function will

• nostrademons 13y ago
  typecheck.static_type is supposed to give you the full type of the object - not just 'function', but 'function(int) -> int'. Or I guess I in this case I was just looking at the return type, so 'int'. Hence the problem - foo is defined so that if its type is int, it returns a string, while if its type is string, it returns an int. The problem with giving up and returning 'dynamic' is that dynamics tend to propagate through the code if you're doing anything moderately complex. If we give up, then any expression that calls foo() now typechecks as 'dynamic', and any expression that calls one of them typechecks as 'dynamic', and so on. You end up with a typechecker that doesn't tell you anything useful about your program, other than that it was dynamically typed. If this is restricted to a few special cases like, say, Django ORM classes or namedtuple, it's not a huge problem, because you can hardcode in specific rules for them (or put in a plugin mechanism). But tricky typing rules abound even in the basic language features; as mentioned above, multiplication does not even have concisely expressible typing rules in Python.