On 4/15/05, Stephen Compall <[EMAIL PROTECTED]> wrote: > `fold' in SRFI-1 mentions that KONS is supposed to be a function. > > If you give a macro to fold, the macro gets expanded and memoized as > such, when the macro is called normally, as it is as an optimization in > the common case of one list. Try passing multiple lists; I bet you will > get a type error on `apply'.
Thanks for taking the time to reply. Please understand that I'm not taking a harsh tone with you at all. But this "not quite a bug" bit me very hard and I'm still stinging a little. I see your point that the documentation mentions that KONS needs to be a procedure. But from a user's perspective, I don't think that I should have to be reading the docs with a lawyer's mindset to avoid this kind of problem. Furthermore, the reason I got bit with this was because I was using REDUCE (an alias for FOLD) with builtin AND as the KONS. Please observe: guile> (fold + 0 '(1 2 3 4 5)) ; works 15 guile> (fold and #t '(#t #t #t)) ; seems okay. #t guile> (fold + 0 '(1 2 3 4 5)) ; WTF?? 0 It will take a lot of fancy talking and beer to make me believe that the above is not a demonstration of a bug. I would strongly disagree with the SRFI's author's opinion that "there's little point in requiring these procedures to do more." In this case, the point would be to make sure that the user (i.e, me) doesn't render the painstakingly crafted software completely useless. > So I would say "it is an error" to pass a macro to fold. Seems like a > serious error, of course, that leaves the system in an undefined state > unlike errors that don't modify the implementation :); I am no authority > on whether this should be fixed (which is the only issue; the fix is > trivial, but has potential philosophical implications). Well, speaking on the authority of being a Guile user, is this the kind of behavior you want Guile to have? This is exactly the reason I left Perl. There is no good reason to have silently failing software. This is even worse, as what has happened is that the implementation has been silently redefined!! I think that, at the very least, this is a bug in the documentation. There should be all kinds of flashing red lights and sirens when this kind of behavior is possible. -- Steve Juranich Tucson, AZ USA _______________________________________________ Guile-user mailing list Guile-user@gnu.org http://lists.gnu.org/mailman/listinfo/guile-user
