Re: Modernize frame-title-format: "%b - GNU Emacs"

[Gregory Heytings]

> > The display engine calls the function which produces the frame's title 
> > very frequently.  You have just made redisplay much slower due to this 
> > call (abbreviate-file-name is a large and complex function, and you 
> > call Lisp on top of that), and caused most redisplay cycles prfoduce 
> > more garbage.  Is it really worth it?
>
> Thanks, I didn't know it was called very frequently.  I think it's most 
> definitely not worth slowing down redisplay.  We should probably replace 
> it with the "%b" we had before.

I'm not sure, but I think using `buffer-file-truename' (as I did in my 
proposal) would eliminate the problems Eli mentioned.  It is a 
(buffer-local) variable, and it is set only once when a buffer is created.