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Re: string is read-only

From: Maxime Devos
Subject: Re: string is read-only
Date: Wed, 3 Aug 2022 12:59:29 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0

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.)


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