GNU bug report logs - #48264
28.0.50; Changing the default for DEFVAR_PER_BUFFER variables takes O(#buffers) time

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Package: emacs;

Reported by: Spencer Baugh <sbaugh <at> catern.com>

Date: Thu, 6 May 2021 20:25:01 UTC

Severity: normal

Found in version 28.0.50

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Message #83 received at 48264 <at> debbugs.gnu.org (full text, mbox):

From: Spencer Baugh <sbaugh <at> catern.com>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 48264 <at> debbugs.gnu.org
Subject: Re: bug#48264: [PATCH v3 03/15] Add and use BUFFER_DEFAULT_VALUE_P
Date: Fri, 07 May 2021 08:49:59 -0400
Eli Zaretskii <eliz <at> gnu.org> writes:
>> From: Spencer Baugh <sbaugh <at> catern.com>
>> Date: Thu,  6 May 2021 17:33:34 -0400
>> Cc: Spencer Baugh <sbaugh <at> catern.com>
>> 
>> This makes the code more clear and allows us to more easily change how
>> this property is determined.
>
> Does it?  Can you explain why you think so?  It looks like we are
> replacing clear code with an equally clear different code.

Well, "if (idx > 0)" as a conditional requires a fair bit of digging in
the implementation of DEFVAR_PER_BUFFER variables to understand.  On the
other hand, "if (BUFFER_DEFAULT_VALUE_P (offset))" is immediately clear:
We're checking if this variable has a default value.

By hiding the implementation detail of "idx", we both remove the need to
know what idx is, and make it easier to later change the implementation
(as a later commit does).




This bug report was last modified 2 years and 290 days ago.

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