A style question
in [Lisp]
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From: Rob Warnock on 28 Feb 2007 23:10 Harald Hanche-Olsen <hanche(a)math.ntnu.no> wrote: +--------------- | + Harald Hanche-Olsen <hanche(a)math.ntnu.no>: | | for fizz in '#3=(nil nil "Fizz" . #3#) | | for buzz in '#5=(nil nil nil nil "Buzz" . #5#) | | But I hadn't read the whole thread and missed Rob Warnock's use of | this same trick in <zZSdnVArCY40vHjYnZ2dnUVZ_ruknZ2d(a)speakeasy.net>. +--------------- But yours is neater [== hackier], since it uses the actual non-NIL generalized boolean values. Mine just used T & NIL in the circular lists and had to provide the "Fizz" and "Buzz" elsewhere... -Rob ----- Rob Warnock <rpw3(a)rpw3.org> 627 26th Avenue <URL:http://rpw3.org/> San Mateo, CA 94403 (650)572-2607
From: John Thingstad on 28 Feb 2007 23:19 On Thu, 01 Mar 2007 04:19:08 +0100, lojic <lojicdotcom(a)gmail.com> wrote: > On Feb 28, 5:39 pm, t...(a)sevak.isi.edu (Thomas A. Russ) wrote: >> Well, OK -- I have gone into the West, but I stopped just short of the >> Pacific Ocean. Obviously this requires some finesse since we don't want >> to have to specify arguments more than once. So we do need to obscurely >> move back and forth along the argument list: >> >> (dotimes (i 20) >> (format t "~[Fizz~:;~]~[Buzz~*~:;~2:*~[~2*~:;~*~D~]~]~%" >> (mod i 3) (mod i 5) i)) >> >> Now this is just way too obscure for me -- and it looks vaguely like >> Perl code ;) > > Disturbing yet impressive. Anyone want to give a hand to the newbie in > understanding the above? > > Brian > Shouldn't be necessary. The key to this cypher is in the ANSI document under format options. -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/
From: Vassil Nikolov on 28 Feb 2007 23:21 On Wed, 28 Feb 2007 14:48:27 +0100, Rainer Joswig <joswig(a)lisp.de> said: | ... | Take this (not written by me). Zmacs? | ... | How about this? This is clearly from aliens. But was ported to Common Lisp at some point, wasn't it? ---Vassil. -- mind mate, n. One of two persons mentally compatible with each other (cf. soul mate).
From: Rob Warnock on 28 Feb 2007 23:29 <nallen05(a)gmail.com> wrote: +--------------- | Rob Warnock wrote: | > This one is both efficient -- *no* MOD calls at all! -- | > *and* so ugly only a parent could love it: ;-} ;-} | > | > (defun fizz-buzz (n) | > (loop for i from 1 to n | > and three-p in '#3=(nil nil t . #3#) | > and five-p in '#5=(nil nil nil nil t . #5#) | > do ... | | This is awsome, Rob ;-) But I can make one that's faster AND uglier! | | (defmacro def-fizz-buzz () | (let (l) | (do* ((i 1 (incf i)) | (m3p (zerop (mod i 3)) | (zerop (mod i 3))) | (m5p (zerop (mod i 5)) | (zerop (mod i 5)))) | ((> i 15)) | (setq l | (list* `(print ,(cond ((and m3p m5p) "FizzBuzz") | (m3p "Buzz") | (m5p "Fizz") | (t 'y))) | '(when (> y x) (return)) | '(incf y) | l))) | `(defun fizz-buzz (x) | (let ((y 0)) | (loop ,@(reverse l)))))) +--------------- Yes!! *That's* how to use macros to write code for you!! ;-} One minor tweak -- instead of: (INCF Y) (WHEN (> Y X) (RETURN)) you could use: (WHEN (> (INCF Y) X) (RETURN)) Another really minor tweak -- in the DO* variable bindings, instead of (M3P (ZEROP (MOD I 3)) (ZEROP (MOD I 3)) you can write (M3P #1=(ZEROP (MOD I 3)) #1#). Now for *lots* of extra credit... ;-} ;-} Write the general version of DEF-FIZZ-BUZZ that accepts a function name (so we can tell them apart) and an alist of primes and strings, and emits similarly-correct/fast code. E.g., the example we've been using all along would be generated like so: (def-fizz-buzz 'fizz-buzz '((3 "Fizz") (5 "Buzz"))) -Rob ----- Rob Warnock <rpw3(a)rpw3.org> 627 26th Avenue <URL:http://rpw3.org/> San Mateo, CA 94403 (650)572-2607
From: lojic on 28 Feb 2007 23:39
On Feb 28, 11:29 pm, r...(a)rpw3.org (Rob Warnock) wrote: > Now for *lots* of extra credit... ;-} ;-} > > Write the general version of DEF-FIZZ-BUZZ that accepts a > function name (so we can tell them apart) and an alist of primes > and strings, and emits similarly-correct/fast code. E.g., the > example we've been using all along would be generated like so: > > (def-fizz-buzz 'fizz-buzz '((3 "Fizz") (5 "Buzz"))) That goes back to my earlier post of the following generalized solution: (defun fizz-buzz (n lst) (do ((i 1 (+ i 1))) ((> i n)) (let ((fizzed nil)) (dolist (obj lst) (let ((a (car obj)) (str (car (cdr obj)))) (when (zerop (mod i a)) (princ str) (setf fizzed t)))) (if (not fizzed) (princ i)) (terpri)))) (fizz-buzz 15 '((3 "Fizz") (5 "Buzz"))) This was my off-the-cuff approach from a non-Lisp background. I would like to see a macro-ized version and get some feedback from the group regarding the appropriateness of macros in this case vs. a simple function as in the above. Brian Adkins > > -Rob > > ----- > Rob Warnock <r...(a)rpw3.org> > 627 26th Avenue <URL:http://rpw3.org/> > San Mateo, CA 94403 (650)572-2607 |