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From: Emanuel Berg <incal@dataswamp.org>
To: help-gnu-emacs@gnu.org
Subject: Re: [External] : Re: Testing whether a list contains at least one non-nil element
Date: Sat, 29 Oct 2022 11:20:10 +0200	[thread overview]
Message-ID: <87r0yr56lx.fsf@dataswamp.org> (raw)
In-Reply-To: 87lep031vm.fsf@web.de

Michael Heerdegen wrote:

>> If you are doing it "by hand", why not indulge in Lisp's
>> "classic elegance", like so:
>>
>>   (defun has-non-nil (lst)
>>     (cond
>>      ((null lst) nil)
>>      ((consp lst) (or (not (null (car lst))) (has-non-nil (cdr lst))))
>>      (t (error "Not a proper list! You cheater!"))))
>
> You don't want to implement such functions in Emacs with
> recursion because you'll easily hit `max-lisp-eval-depth'
> when they are called. Sorry to tell you, but a loop is the
> preferable way in Elisp.

He knows that ...
>
-- 
underground experts united
https://dataswamp.org/~incal




  parent reply	other threads:[~2022-10-29  9:20 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-25 10:16 Testing whether a list contains at least one non-nil element Heime
2022-10-25 10:46 ` Jean Louis
2022-10-25 10:47 ` Jean Louis
2022-10-25 10:50 ` Jean Louis
2022-10-25 12:12   ` Emanuel Berg
2022-10-26 18:56     ` Jean Louis
2022-10-27  3:54       ` [External] : " Drew Adams
2022-10-27  4:53         ` Jean Louis
2022-10-27  5:30           ` Emanuel Berg
2022-10-27 15:54           ` Drew Adams
2022-10-27 17:47             ` Elisp and CL (was: Re: [External] : Re: Testing whether a list contains at least one non-nil element) Emanuel Berg
2022-10-27 20:38             ` [External] : Re: Testing whether a list contains at least one non-nil element Jean Louis
2022-10-28  0:22               ` Emanuel Berg
2022-10-28  4:48               ` tomas
2022-10-28  5:19                 ` Jean Louis
2022-10-28  6:20                 ` Michael Heerdegen
2022-10-28 13:09                   ` Stefan Monnier via Users list for the GNU Emacs text editor
2022-10-29  6:10                     ` Michael Heerdegen
2022-10-29 15:25                       ` Stefan Monnier via Users list for the GNU Emacs text editor
2022-10-30 12:49                         ` Emanuel Berg
2022-10-29  6:38                     ` tomas
2022-10-30 12:48                     ` Emanuel Berg
2022-10-29  9:20                   ` Emanuel Berg [this message]
2022-10-29  9:19                 ` Emanuel Berg
2022-10-27  4:01       ` Emanuel Berg
2022-10-25 12:05 ` Michael Heerdegen
2022-10-25 12:15   ` Emanuel Berg
2022-10-25 15:59   ` [External] : " Drew Adams
2022-10-25 17:44     ` Emanuel Berg
2022-10-26 15:39       ` Drew Adams
2022-10-26 17:43         ` Emanuel Berg
2022-10-25 17:25 ` Joost Kremers
2022-10-25 17:51   ` Emanuel Berg
2022-10-25 19:44   ` Heime
2022-10-25 20:08     ` Joost Kremers
2022-10-25 20:15     ` [External] : " Drew Adams
2022-10-25 20:19       ` Joost Kremers
2022-10-26  3:00         ` Stefan Monnier via Users list for the GNU Emacs text editor
  -- strict thread matches above, loose matches on Subject: below --
2022-10-28  5:07 Drew Adams

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