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From: Benny Sum <benny.sum@gmail.com>
To: help-gnu-emacs@gnu.org
Subject: Re: Question on frame title
Date: Fri, 16 Oct 2015 04:05:48 -0700 (PDT)	[thread overview]
Message-ID: <6070a8cb-fb0f-4986-836c-296b9b4fac5b@googlegroups.com> (raw)
In-Reply-To: <mailman.405.1444931478.7904.help-gnu-emacs@gnu.org>

On Thursday, October 15, 2015 at 1:51:21 PM UTC-4, Random832 wrote:
> Random832 <random832@fastmail.com> writes:
> > This will re-execute the info-data command every time you switch
> > buffers. If the command is expensive, you may want to store the value in
> > a buffer-local variable.
> 
> Actually it turns out it evaluates quite a bit more often than that. I
> can't quite find the rhyme or reason to precisely when it gets evaluated.
> 
> Fun little test script:
> 
> (setq test-index 0)
> (setq frame-title-format
>       '(:eval (format "frame-title-format evaluated %d times "
>                       (setq test-index (1+ test-index)))))
> 
> It gets evaluated when:
> 
> - Changing buffers
> - Changing windows
> - (Yes, that's even when it's the same window, or the same buffer)
> - (Even the minibuffer. Sometimes.)
> - Activating the mark
> - Deactivating the mark
> - Clicking the mouse anywhere (and again on release)
> 
> Probably best to try to get the value in a buffer-local variable.

Yes, it is very slow.  How do I get the value in a buffer-local variable?


  parent reply	other threads:[~2015-10-16 11:05 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-15 15:26 Question on frame title Benny Sum
2015-10-15 16:26 ` Marcin Borkowski
     [not found] ` <mailman.391.1444926481.7904.help-gnu-emacs@gnu.org>
2015-10-15 16:43   ` Benny Sum
2015-10-15 17:21     ` Marcin Borkowski
2015-10-15 17:30     ` Random832
2015-10-15 17:49       ` Random832
     [not found]       ` <mailman.405.1444931478.7904.help-gnu-emacs@gnu.org>
2015-10-16 11:05         ` Benny Sum [this message]
2015-10-16 13:35           ` Random832
     [not found]           ` <mailman.455.1445002561.7904.help-gnu-emacs@gnu.org>
2015-10-16 18:15             ` Benny Sum
2015-10-16 19:14               ` Benny Sum
     [not found]     ` <mailman.402.1444930342.7904.help-gnu-emacs@gnu.org>
2015-10-15 23:08       ` Benny Sum

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