[gambit-list] Determine if symbol is bound

Adrien Piérard pierarda at iro.umontreal.ca
Mon May 9 05:51:00 EDT 2011

What about this?

(define-macro (bound? x)
     (lambda (e) #f)
     (lambda () (and ,x #t))))

(pp (bound? x))
(let ((y 3))
  (pp (bound? y)))



2011/5/9 William James <w_a_x_man at yahoo.com>:
> How do you check to see if a symbol is already bound?
> To be used in this fashion:
> (if (bound? x)
>  (set! x 22)
>  (define x 22))
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