From: Dirk Bernhardt
Subject: (random) in CLISP
Date: Mon, 20 Sep 2004 18:55:11 +0000
Message-ID: <2r8nc1F15eui3U1@uni-berlin.de>

Hi there,

is the (random)-implementation in CLISP non-standard? I use the current 
cygwin CLISP (v2.33.1), and the CLHS example:

  (setq snap-shot (make-random-state))
  ;; The series from any given point is random,
  ;; but if you backtrack to that point, you get the same series.
  (list (loop for i from 1 to 10 collect (random))
        (let ((*random-state* snap-shot))
          (loop for i from 1 to 10 collect (random)))
        (loop for i from 1 to 10 collect (random))
        (let ((*random-state* snap-shot))
          (loop for i from 1 to 10 collect (random))))

fails with an error saying random needs more parameters.

Thanks,
Dirk

• Re: (random) in CLISP Peter Seibel
• Re: (random) in CLISP Dirk Bernhardt

From: Peter Seibel
Subject: Re: (random) in CLISP
Date: Mon, 20 Sep 2004 19:10:05 +0000
Message-ID: <m37jqoep6z.fsf@javamonkey.com>

Dirk Bernhardt <······@krid.de> writes:

> Hi there,
>
> is the (random)-implementation in CLISP non-standard? I use the
> current cygwin CLISP (v2.33.1), and the CLHS example:
>
>   (setq snap-shot (make-random-state))
>   ;; The series from any given point is random,
>   ;; but if you backtrack to that point, you get the same series.
>   (list (loop for i from 1 to 10 collect (random))
>         (let ((*random-state* snap-shot))
>           (loop for i from 1 to 10 collect (random)))
>         (loop for i from 1 to 10 collect (random))
>         (let ((*random-state* snap-shot))
>           (loop for i from 1 to 10 collect (random))))
>
> fails with an error saying random needs more parameters.

The error message seems right--per the CHS you must supply at least
one argument--the limit. It also takes a random state object as a
second, optional, argument. (Hmmm. Looks like the example in the
*RANDOM-STATE* dictionary entry is busted. Try adding an argument such
as 100 to all the calls to RANDOM.

-Peter

-- 
Peter Seibel                                      ·····@javamonkey.com

         Lisp is the red pill. -- John Fraser, comp.lang.lisp

From: Dirk Bernhardt
Subject: Re: (random) in CLISP
Date: Mon, 20 Sep 2004 19:02:26 +0000
Message-ID: <2r8npjF17g4f1U1@uni-berlin.de>

Dirk Bernhardt wrote:

> is the (random)-implementation in CLISP non-standard? I use the current 
> cygwin CLISP (v2.33.1), and the CLHS example:

Nevermind, the example in CLHS is wrong. random needs a parameter, and 
thus works:

  (setq snap-shot (make-random-state))
  ;; The series from any given point is random,
  ;; but if you backtrack to that point, you get the same series.
  (list (loop for i from 1 to 10 collect (random 1000))
        (let ((*random-state* snap-shot))
          (loop for i from 1 to 10 collect (random 1000)))
        (loop for i from 1 to 10 collect (random 1000))
        (let ((*random-state* snap-shot))
          (loop for i from 1 to 10 collect (random 1000))))

Cheers,
Dirk