bug#21588: 25.0.50: Single quotes becoming curvy quotes in message function

[Paul Eggert]

On 09/30/2015 08:54 PM, Kaushal Modi wrote:
> - Can the default be changed to 'grave?

The GNU coding standards were changed a while ago to recommend against grave 
quoting in diagnostics and many GNU applications have already changed (e.g., 
coreutils, GCC).  Although Emacs has been one of the holdouts, now is as good a 
time as any to make the move.

> we need to update the documentation that warns the user to use the correct 
> style.

Thanks, done in the attached patch, which I just installed in the master branch.

> it is mentioned that typewriter quotes are simple and portable.

That discussion was intended to be about text files, so I added a phrase to that 
effect in the attached patch.  This should help resolve the seeming contradiction.

> If we want to keep the default of text-quoting-style as nil (or 'curve), more 
> logic needs to be added that decides whether left curly quote or right curly 
> quote should be used, which might have some performance impact as we then need 
> to check what the previous character is, what the next character is, etc to 
> decide if the current apostrophe needs to be replaced with a left or a right 
> quote.

It’s not a significant performance impact.  It’s more a hassle of documenting a 
more-complex approach.  That is partly why I gave up on such an approach after 
implementing it, and went with the simpler approach that is in Emacs master now.

> CASE 1: 'Hey' -> ‘Hey’
> CASE 2: it's awesome -> it’s awesome
> CASE 3: my sisters' weddings -> my sisters’ weddings
> CASE 4: He said 'It's awesome!' -> He said ‘It’s awesome!’

‘message’ already does cases 2 and 3 that way, as well as the 2nd apostrophe in 
case 4.  The remaining cases are quite rare in Emacs diagnostics, as the Emacs 
style uses directed quotes when single-quoting.

> If there's a non-space character before the apostrophe, replace it with right 
> quote, else use left quote.

That would mishandle common English phrases like “'60s pop culture” and “rock 
'n' roll”.  (These phrases don’t occur in Emacs diagnostics either, but as long 
as we’re being pedantic....)  Any heuristics will go awry sometimes so we need 
some way to override the heuristics; and once we have such an override, there is 
a real benefit to keeping the heuristics simple.

0001-Fix-a-few-problems-with-directed-quotes.patch
Description: Text document