bug#20707: [PROPOSED PATCH] Use curved quoting in C-generated errors

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

On 06/10/2015 12:17 PM, Alan Mackenzie wrote:
> It seems to me, judging by the number of questions relating to Emacs on
> the Linux console I've answered over the years, the number of users is
> not small.

I'm afraid there was a miscommunication there.  My message was not about 
people who use the Linux console, a small but hardy band of hackers.  It 
was about people who use the Linux console in an awful mode that can't 
display curved single quotes.  That's not you, and it's not me (and I do 
use Emacs on the Linux console and I haven't configured it specially), 
and I doubt whether it's RMS either. Perhaps some people use Emacs that 
way occasionally, but I'm skeptical that this is a significant problem.  
If it is, we can easily solve it by automatically doing in Emacs the 
equivalent of the font substitution I gave the shell script for in a 
recent message.  So this issue is not a fundamental obstacle to the change.

> My proposition is that string literals remain constants
> just as they are now.  The decision would be made at configuration time,
> and a trivial #ifdef in the reader would decide at build time how to
> expand the escaped quotes.

Making them constants removes the most serious objection I had to the 
idea.  I wouldn't favor writing documentation that way, as it's ugly to 
quote \`like this\' when it can easily be quoted ‘like this’.  But it 
could be useful for people who prefer its minor ugliness to having to 
learn how to type curved quotes, so I suppose we can add it.

However, the configuration-time switch sounds like a non-starter, as it 
would be one more source of portability hassles and it shouldn't be 
needed if we get the display problems fixed, which we need to fix 
anyway.  That is, the escapes should simply generate curved single 
quotes on all platforms.