[plt-scheme] The Scheme way of: Using 'global' variables ?

Hello all,

After C/Java/Python, I have been exclusively using Scheme (plt-scheme) 
for my day-day programming fun. Now, I have started facing situations 
where I simply am not sure the correct way to do something in Scheme. 
The latest case was something like this:

I needed to use a 'global' identifier in my program, where I had some 
procedures,  couple of which needed R/W access respectively and I wanted 
the value to persist for the lifetime of the program- just the way it 
happens for variables you define at the topmost level in say, C.

So, what I did in scheme is- I just defined using (define var 0) and 
used (set!..) to change value in one procedure and used the identifier 
name itself in some other procedure.

For eg,

<code>

(define var 0)

(define (proc1) (set! var (+ 1 var)))

; some other procs
; in
; between
;

(define (proc2) (display var))

</code>

But, I think this is not the way this should be done in Scheme, because 
global variables is just calling for trouble in large programs. At the 
same time, I am not sure how to achieve the same thing in a better way, 
if there is one..


PS: plt-scheme just has the necessary batteries to get started easily in 
Scheme :)

Thanks a lot.

Best Regards,
Amit

-- 
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