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From: Maxime Devos <maximedevos@telenet.be>
To: Damien Mattei <damien.mattei@gmail.com>
Cc: guile-user <guile-user@gnu.org>, guile-devel <guile-devel@gnu.org>
Subject: Re: string is read-only
Date: Wed, 3 Aug 2022 12:59:29 +0200	[thread overview]
Message-ID: <1371f495-e708-b441-ff9c-8beb9f667573@telenet.be> (raw)
In-Reply-To: <CADEOade2yJejoXkOKPojRF_N8DpkK934TozevdM0AHA6Qxh-JQ@mail.gmail.com>


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On 03-08-2022 12:55, Damien Mattei wrote:
> but no restrictions with lists in Guile:
> scheme@(guile-user)> (define lst '(1 2 3))
> scheme@(guile-user)> (set-car! lst 7)
> scheme@(guile-user)> lst
> (7 2 3)

Non-empty lists are pairs and the second part of the pair is another 
list -- in Guile, this is effectively implement as having the second 
part (the cdr) be a kind of pointer.

Pointers need relocation, so lists cannot be put in read-only sections 
(unless something like RELRO is used), and in Guile pairs do not have 
'am I read-only' metadata (unlike strings).

(My unverified hypothesis on why you aren't seeing an error here.)

Greetings,
Maxime.


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  reply	other threads:[~2022-08-03 10:59 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-03  9:12 string is read-only Damien Mattei
2022-08-03  9:32 ` Thomas Morley
     [not found]   ` <CADEOadctjXAyZfwYG3Qbky129i0NBbM+HK6g1iUwvA_HrT4UxA@mail.gmail.com>
2022-08-03  9:51     ` Fwd: " Damien Mattei
2022-08-03  9:59       ` Maxime Devos
2022-08-03  9:41 ` Maxime Devos
2022-08-03  9:57   ` Ricardo G. Herdt
2022-08-03 10:55   ` Damien Mattei
2022-08-03 10:59     ` Maxime Devos [this message]
2022-08-03 11:34       ` Damien Mattei
2022-08-03  9:42 ` Taylan Kammer
2022-08-03  9:50   ` Jean Abou Samra
2022-08-03 10:30     ` Taylan Kammer
2022-08-03 10:33       ` Jean Abou Samra
  -- strict thread matches above, loose matches on Subject: below --
2022-08-03 11:55 Pierpaolo Bernardi
2022-08-03 12:48 ` Damien Mattei

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