Re: [Emacs-diffs] master 9ffb6ce 5/5: Quoting fixes in lisp/international and lisp/leim

[Alan Mackenzie <acm@muc.de>]

Hello, Paul.

On Thu, Sep 03, 2015 at 07:56:05AM -0700, Paul Eggert wrote:
> Alan Mackenzie wrote:
> > the original scenario had nothing to do with
> > `text-quoting-style'.

> There seemed little point to having two variables to control text quoting 
> behavior, one for initial inference of display quoting and one for translation 
> of help strings and diagnostics.  So I used the same variable for all three.

At the initial setup, there aren't yet configuration variables, are
there?  .emacs hasn't yet been read.

> > You've cut so much context

> To help move things forward, here's a complete copy of the message I replied to, 
> along with a copy of my reply inserted at the appropriate spot, so that you can 
> see the complete context.

Thanks for that.  Yesterday wasn't a good day.

> > Alan Mackenzie wrote:

> >> On Wed, Sep 02, 2015 at 09:32:42AM -0700, Paul Eggert wrote:
> >>> Alan Mackenzie wrote:
> >>>> Using my  standard font, lat1-16, the curly quotes use the same glyphs as
> >>>> ` and ', hence are visibly indistinguishable from them.

> >>> That's no longer true as of yesterday's master commit
> >>> 1a3518e7c361a9ceaa017c1334a83d14e0651a4e.

> >> I'm afraid it is still true.  After doing a C-h f c-mode, apparent
> >> quotes were in the buffer.  Checking them with C-u C-x =, they were
> >> indeed curly quotes, but were displayed the same as ASCII quotes.

I've just updated my git-master Emacs again, and the situation still
holds: With emacs -Q, C-h f c-mode displays a buffer containing curly
quotes, these curly quotes being visibly indistinguishable from ASCII
quotes.

In particular, I've not seen any shadowed quotes on my screen no matter
what I've done.

> > After fooling around with it on my Linux console, I came up with a
> > scenario that had the behavior you describe.  In this scenario I set
> > the LC_ALL environment variable to en_US.UTF-8 even though the Linux
> > console could display only a few non-ASCII characters (so in some
> > sense this is a misconfiguration).  And I put (setq
> > text-quoting-style 'grave) into my ~/.emacs file, indicating that I
> > wanted traditional ASCII quoting.

After I execute M-: (setq text-quoting-style 'grave), my next C-h f does
indeed use ASCII quotes.

> > Emacs didn't look at the text-quoting-style setting when configuring
> > the display table at startup, which seems wrong, so I patched master
> > to fix that.  Please do a git pull and give it a try.

Done.  See above.  But isn't startup done before processing .emacs?

> > If it still doesn't work for you, please send the output of the shell
> > command ‘locale’ just before invoking Emacs, and the output of the
> > command ‘echo $TERM’, and a copy of the Lisp code that sets
> > text-quoting-style in your ~/.emacs file.  Thanks.

Just for completeness's sake, I have $TERM=linux, no LC_.. variable is
set, and I don't yet have `text-quoting-style' in my .emacs, but will
probably write (setq text-quoting-style 'grave) into it at some stage.

> >>> On a terminal that cannot display curved quotes, ...

Incidentally, I just tried running Emacs under X Windows, and there I
found the two curly quotes visibly indistinguishable from each other,
except with a lot of effort, and they were both indistinguishable from
the ASCII apostrophe, unless there was one nearby on the screen to
compare with.

> >> Currently, my terminal is not such a one.  It _can_ display curly
> >> quotes, but only identically to ASCII quotes.  `char-displayable-p'
> >> returns 'unicode for them.

`char-displayable-p' isn't very useful here.  It does not check whether a
glyph is assigned to a character code, and I don't even think Linux
offers a suitable interface for this.

> >> The issue is not so much whether a terminal can display curly quotes,
> >> rather it's whether a user wants them to be used or not.

> >>> .... Emacs master now uses different glyphs for the quotes’ ASCII
> >>> replacements, because the replacements are shadowed.  The shadowed
> >>> glyphs are easily distinguishable on my Linux console.  Users
> >>> shouldn’t need to configure Emacs specially, or their Linux console
> >>> specially, to get this behavior.  So this objection no longer applies.

-- 
Alan Mackenzie (Nuremberg, Germany).