Re: `save-excursion' defeated by `set-buffer'

[Uday Reddy]

On 3/12/2011 7:56 PM, Drew Adams wrote:

> But this has already been expressed (by several people), and rejected, in
> various discussions in emacs-devel@gnu.org.

I believe I was the one that last raised it in emacs-devel and, after 
the explanations from Stefan Monnier and Stephen Turnbull, I was 
satisfied.  I told you quite explicitly that I was satisfied.

> IMO, this warning has produced _far_ more confusion than it has eliminated.  And
> that will no doubt continue to be the case going forward.

Yes, I agree that this saga will continue for quite some time.  But I 
wouldn't say that the warning has produced all this confusion.  The 
confusion about how to use save-excursion correctly has existed for a 
long time and continues to exist.  The warning is the messenger, not the 
cause of the confusion.

> FWIW, I also agree with Andreas that a "warning" is for something serious.  A
> warning is not the same thing as in informative message.  A warning _warns_ you
> about potential danger/damage.  Alarmism eventually results in the Chicken
> Little effect (aka Boy Cries "Wolf!").

This particular warning is in the 'suspicious category.  It signals that 
the code is suspicious.  I for one would be very wary of using anybody's 
code that generates such warnings.  The warnings would signal to me that 
the developers have not taken care to use the programming language 
correctly.  They have produced code that happens to work but could break 
easily when pulled and stretched.

Cheers,
Uday