[TYPES] Types of expressions in dynamic languages: "un-typed" or "uni-typed"?

[Uday S Reddy]

Sean McDirmid writes:

> Pragmatically, the programmer is still able to talk about "ducks" in
> Python even if the check to see if a value can be used as a duck occurs
> dynamically. Explaining to the programmer that Python only has one type
> would be very unfriendly and confusing when clearly one can talk about
> ducks that quack in the language without much problems.

I think this is an excellent point.  There can be other ways of enforcing
type abstractions in a programming language than by static typing rules.
For that reason, "untyped programming language" is a misnomer.  (Perhaps it
was imported thoughtlessly from mathematics, where something like the
Zermelo-Fraenkel set theory is genuinely untyped.)

I always refer to such languages as "dynamically typed" languages rather
than "untyped" languages.

Please see this discussion on Stack Exchange which is closely related:

http://cs.stackexchange.com/questions/2301/categorisation-of-type-systems-strong-weak-dynamic-static/

Cheers,
Uday