9 Mai
2011
9 Mai
'11
05:51
What about this? (define-macro (bound? x) `(with-exception-handler (lambda (e) #f) (lambda () (and ,x #t)))) (pp (bound? x)) (let ((y 3)) (pp (bound? y))) Cheers, P! 2011/5/9 William James <w_a_x_man@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)) _______________________________________________ Gambit-list mailing list Gambit-list@iro.umontreal.ca https://webmail.iro.umontreal.ca/mailman/listinfo/gambit-list
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