[plt-scheme] (typeof obj)

Shriram Krishnamurthi wrote:
> What is the type of ADD1?  What is the type of CALL/CC?  How
> about of (lambda (x) x)?  Or
>
>  (let ([x 3])
>    (lambda (y)
>      (when (= (random 2) 0)
>          (set! x y))
>      x))
>
> ?
>
procedure.
> Once you answer those questions we can resolve many of the
> things that have been said on this thread (such as "the Scheme
> system always knows the type of every object").
>
> Shriram
>
> PS: In general, when asking questions about "every object" in
>    a language like Scheme, it's imperative to remember the
>    higher-order values also.