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From: Emanuel Berg <incal@dataswamp.org>
To: help-gnu-emacs@gnu.org
Subject: Re: Calling a function with undefined symbol
Date: Thu, 03 Nov 2022 13:15:45 +0100	[thread overview]
Message-ID: <87o7toi68e.fsf@dataswamp.org> (raw)
In-Reply-To: 87r0yk9tw6.fsf@web.de

Michael Heerdegen wrote:

>> Yes, but why do you need the "strange value" for that?
>
> I chose it because you get an `equal' value when you quote
> the value (to suggest a wrong track to an answer), and

You do?

(setq print-circle t)

(setq x #1=(quote #1#))

(eq    'x x) ; nil
(equal 'x x) ; nil

?

> Ok - so here is part two of the exercise to check whether
> you have understood quoting. Is the `length' of this strange
> value `''''''...`
>
>   (a) 0   or
>   (b) 1   or
>   (c) 2   or
>   (d) infinite/undefined ?

The length is 2 (it's a list) because `quote' does not
evaluate anything, not even itself, however this pattern is
repeated at the second element so there it is either cyclic or
indefinite,

  (quote (quote (quote ... )))

So the length is 2, but the depth is infinite. IOW: It's a trap!

-- 
underground experts united
https://dataswamp.org/~incal




  reply	other threads:[~2022-11-03 12:15 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-31  8:15 Calling a function with undefined symbol Heime
2022-10-31  8:32 ` Jean Abou Samra
2022-10-31  8:42 ` tomas
2022-10-31  8:57   ` Heime
2022-10-31  9:07     ` tomas
2022-10-31  9:24     ` Jean Abou Samra
2022-10-31  9:43       ` Heime
2022-10-31  9:58         ` Jean Abou Samra
2022-10-31 10:57           ` Heime
2022-10-31 17:00           ` [External] : " Drew Adams
2022-10-31 17:10             ` Emanuel Berg
2022-11-01  4:11               ` Drew Adams
2022-11-01  5:24               ` tomas
2022-11-01 15:58                 ` Drew Adams
2022-11-01 16:13                   ` tomas
2022-11-01 19:22                     ` Drew Adams
2022-10-31 12:29   ` Stefan Monnier via Users list for the GNU Emacs text editor
2022-10-31 15:37     ` Emanuel Berg
2022-11-02 12:14     ` Michael Heerdegen
2022-11-02 14:25       ` Sam Steingold
2022-11-02 16:40         ` Michael Heerdegen
2022-11-02 17:28           ` Emanuel Berg
2022-11-02 23:04           ` Emanuel Berg
2022-11-03 11:09             ` Michael Heerdegen
2022-11-03 12:15               ` Emanuel Berg [this message]
2022-11-04 12:16                 ` Michael Heerdegen
2022-11-05 14:32                   ` Emanuel Berg
2022-11-05 23:22                     ` Michael Heerdegen
2022-11-06 20:17                       ` Emanuel Berg
2022-11-07 16:03                         ` Michael Heerdegen
2022-11-07 16:50                           ` [External] : " Drew Adams
2022-11-07 16:52                           ` Emanuel Berg
2022-11-08 15:52                             ` Michael Heerdegen
2022-11-08 19:15                               ` tomas
2022-11-08 19:57                                 ` Michael Heerdegen
2022-11-08 20:47                                   ` tomas
2022-11-08 21:35                               ` Sam Steingold
2022-11-08 23:53                                 ` Michael Heerdegen
2022-11-09 15:32                                   ` Sam Steingold
2022-11-09 15:59                                     ` Michael Heerdegen
2022-11-16 19:07                               ` Emanuel Berg
2022-11-16 21:40                                 ` [External] : " Drew Adams
2022-11-16 21:55                                   ` Emanuel Berg
2022-11-04 14:33                 ` Michael Heerdegen
2022-11-05 12:57                   ` Emanuel Berg
2022-10-31 11:34 ` Emanuel Berg

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