Re: [pro] Sub-function free variable binding differences between Scheme and CL
Burton Samograd burton.samog...@gmail.com writes: Hello, I am curently translating the logic circuit simulator code from SICP into Common Lisp and have run into a snag that I would like to ask about. The Scheme code is as follows from section 3.3.4 (page 223 of my hardcover edition): (define (and-gate a1 a2 output) (define (and-action-procedure) (let ((new-value (locical-and (get-signal a1) (get-signal a2 (after-delay and-gat-delay (lambda () (set-signal! output new-value) (add-action! a1 and-action-procedure) (add-action! a2 and-action-procedure)) The code basically binds the local function and-action-procedure into a list of functions in a1 and a2 which are then called by another routine later to perform the action when a value is set on the wire. My translated Common Lisp code is: (defun make-and-gate (a1 a2 output) (flet ((logical-and (a b) (if (= a 1) b a)) (and-action-proc () (let ((new-value (logical-and (get-signal a1) (get-signal a2 (set-signal output new-value (add-action a1 #'and-action-proc) (add-action a2 #'and-action-proc))) You should use LABELS instead of FLET, FLET doesn't make its definitions available inside definitions so the call logical-and in and-action-proc can't find logical-and. And seriously, writing to the _pro_ mailing list to ask trivial questions? -- With best regards, Stas. ___ pro mailing list pro@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/pro
Re: [pro] Sub-function free variable binding differences between Scheme and CL
Burton Samograd burton.samog...@gmail.com writes: I apologize, my original code was using labels but I copied the one using flet for this question. Please assume that I am using labels; the variable binding question still stands. With labels, the code is right, that means either you're not telling something else again, or the problem is in another place in the code. -- With best regards, Stas. ___ pro mailing list pro@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/pro
