Sorry, Matthias, that was dumb of me to post my solution. What should I have done? Should I have just asserted there was no real use of ormap & andmap in HtDP? Should I have said that that exercise didn't IMO require andmap? Should I not have discussed the exercise at all? Is this even a good list to ask questions about good program design?
David, I didn't understand what your code was supposed to show. That's good you know how to replicate draw.ss in universe. I thought about doing it, as the docs point you that way, but didn't see how. Why do you think that HtDP's ormap is different from Racket's ormap? HtDP Figure 57: ;; ormap : (X -> boolean) (listof X) -> boolean ;; to determine whether p holds for at least one item on alox ;; that is, (ormap p (list x-1 ... x-n)) = (or (p x-1) (or ... (p x-n))) That's the ormap described when you hit: ormap provided from racket/base, racket Now that's a bit different from what's described when you hit: ormap provided from lang/htdp-advanced (ormap p (list x-1 ... x-n)) = (or (p x-1) ... (p x-n)) I assume that's a documentation bug, as Advanced Student has set!, so it matters if you evaluate all the later (p x-i)s after you get a non-#f value. I should try it out to be sure. _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
