Re: Question about bindings & STklos objects

From: Erick Gallesio <eg_at_kaolin.unice.fr>
Date: Mon, 28 Nov 1994 14:18:17 +0000

> To what extent can an address be used in place of a variable?
>
> For example, the following didn't work:
>
> STk> (define a '(p d q))
> #[undefined]
> STk> (car a)
> p
> STk> (car (address-of a))
>
> *** Error:
> car: wrong type of argument: "#pf0f64"
> STk>

addrees-of is a kludge and I hop to be able to avoid its usage in a near
future
(of course it address-of will be supported for compatibility).

To respond to the original question, address and varibale are not
interchangable. In fact address-of returns an object of type "address"
(i.e. address? on it will yield #t). You must use read to find the value
associated to the given address. Following code illustrate this

  STk> (define a '(p d q))
  #[undefined]
  STk> (read-from-string (format #f "~A" (address-of a)))
  (p d q)
  STk>

With Tk you don't see this problem since since a Tk result is always a string
which is passed to the reader for building the Scheme result.





                -- Erick
Received on Mon Nov 28 1994 - 14:18:17 CET