Re: [Emacs-diffs] master 9ce1d38: Use curved quotes in core elisp diagnostics

[Paul Eggert <eggert@cs.ucla.edu>]

Dmitry Gutov wrote:
> On 08/17/2015 06:44 AM, Paul Eggert wrote:
>
>> No, as that would break usages such as (format "\\`%s\\'" (car e)).
>> This sort of thing is reasonably common, so it'd be a compatibility
>> problem to change ‘format’ to replace accent-grave.
>
> But it's not a compatibility problem to replace a relatively-rare combination of
> characters? Just because the odds of it coming up are lower?

Yes, of course.  When we change how Emacs behaves, it's important to see how 
likely these changes break existing uses in significant ways.  If the odds are 
significantly nonzero, as would be the case if we changed the behavior of 
(format "...`..." ...), then we have a significant compatibility problem.  In 
contrast, if the odds are very low -- the latter being true for 
(substitute-command-keys "...`...")) -- then we should be OK.