bug#20385: [PATCH] Support curved quotes in doc strings

[Dmitry Gutov <dgutov@yandex.ru>]

On 05/16/2015 12:13 AM, Paul Eggert wrote:

> In contrast, if we use curved quotes in the source, cutting and pasting
> will work naturally.  It's true that here if the display doesn't support
> curved quotes (the atypical case) then cutting and pasting may not work
> -- but that's not a problem we need to worry about, since it's rare
> nowadays particularly among developers.

What if the locale mandates the use of some other kind of quotes? Then 
copying and pasting won't work anyway.

In any case, I've never had a need to copy a diagnostic message with the 
intention to paste it into the source code. Web search or bug report? 
Sure, but never that.

> That will all require explanation, indefinitely.  And this won't be as
> easy as one might think, particularly if opt-out is common.

I've never noticed turning lambda into λ while rendering to be a 
significant problem among users, as long as copy and paste works.

> I suppose it might work in some cases (killing and yanking within a
> single GUI Emacs, say) but not in others (cutting from one Emacs running
> remotely under gnome-terminal and pasting into another in a different
> locale).  The other cases are common enough that they will be a
> continuing hassle.

Again, if there are different locales involved, and you intend to honor 
their different quotings, copying and pasting won't work anyway.

Actually, it's a decent argument against using *any particular locale's* 
quoting, in order not to confuse casual contributors, who'd have to know 
that *these* fancy quotes will be localized, but *those* - won't.

> This sounds backwards.  Even now, one can cut curved quotes from an Info
> file and paste them into a .texi file and it will work, on a typical
> system with proper UTF-8 support (and assuming the latest Emacs on the
> master branch and Texinfo 5).

Maybe you could paste quotes, but not any other kind of formatting. So 
nobody will be too surprised that you can't, in general, paste quotes too.

> Sorry, I meant tildify-space.  (I mixed up functions:
> prettify-symbols-mode uses a different Unicode character, namely ≤.)

Yes, it does - as a part of content, not markup.

And you can notice that if we delimited docstrings with curly quotes 
instead of the straight quotation marks, tildify-space wouldn't have 
been able to use them exactly this way inside the docstring.

> Had these uses been there 20 years or go, or even 10, we would
> have had significant problems in practice; but nowadays, UTF-8 is not a
> problem.

I know of no serious markup language that utilizes unicode, even now.

> I'm not so sure, given the cutting-and-pasting issues mentioned above.
> But even if you're right there would still be a tradeoff: would we want
> a trivial transition now to a complex and klunky approach long-term, or
> a nontrivial transition now to a simple and intuitive approach
> long-term?  Let's strive for simplicity.

Guess I don't see it as clunky. Using ASCII in markup and rendering in 
to something fancier later is fairly common approach.

And the benefits are marginal either way. We have bigger difficulties 
(how to delimit code blocks in docstrings and comments, for instance), 
but here we are discussing changing something that has been working fine 
for years.