From: Maxime Devos <maximedevos@telenet.be>
To: lloda <lloda@sarc.name>
Cc: guile-devel@gnu.org
Subject: Re: [PATCH] New function array-mutable?
Date: Thu, 09 Dec 2021 20:34:00 +0000 [thread overview]
Message-ID: <e8dbdf613b701a958dab5ce3db06a25b7e01dff9.camel@telenet.be> (raw)
In-Reply-To: <97DC61EC-3DD4-444B-98DB-AB9A823EA1F3@sarc.name>
Hi,
lloda schreef op do 25-11-2021 om 20:08 [+0100]:
I think literal arrays are always immutable, and one could base the
test on that.
>
Is such a function useful in some other context? If one has an array which is already immutable, it can be referenced freely and copying it seems unnecessary. If one has a mutable array, is there any reason why one would want to make an immutable copy?
To avoid accidental mutation (though at the cost of making a copy).
Also, literals aren't necessarily immutable if 'eval' is used:
(let ((literal (make-array 0 1 1))) (eval `(array-set! ',literal #xff 0 0) (current-module)) literal)
;; output: #2((255))
As-is, this is a somewhat contrived example. But 'eval' is useful REPL-like things,
and if someone implements a REPL-like thing, they might want to ‘immutabilise’
all input first such that array-set! on literals will actually produce an exception
as one would expect.
An alternative method would be to compile the code before running
(which is what the standard REPL does IIUC), but _requiring_ this extra step seems
suboptimal to me.
Greetings,
Maxime.
p.s. Somehow, your e-mail ended up in spam, for no apparent reason.
next prev parent reply other threads:[~2021-12-09 20:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-25 16:40 [PATCH] New function array-mutable? lloda
2021-11-25 18:19 ` Maxime Devos
2021-11-25 19:10 ` lloda
[not found] ` <97DC61EC-3DD4-444B-98DB-AB9A823EA1F3@sarc.name>
2021-12-09 20:34 ` Maxime Devos [this message]
2021-11-25 18:22 ` Maxime Devos
2021-11-25 18:56 ` lloda
2021-11-27 8:42 ` lloda
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