bug#36307: 26.2; Interaction between electric-pair and electric-quote

[Gustavo Barros <gusbrs.2016@gmail.com>]

I've been looking further into this, and have some things to add.

I had missed two things in the current available structure when I first wrote. 
The first is =electric-quote-context-sensitive=, which I don't know how I had 
missed.  This means the suggestion I made to have a context sensitive electric 
quote is already in place.

The second thing I had missed is how convenient the typing strategy 
implemented by electric quote can be, in the appropriate (or more common) 
setting.  The reason I had failed to see this is that I use a pt_br keyboard 
where the backtick key is both a shift key and an accent key, that is, I had 
to press it four times holding shift to get a double quote.  Having found out 
about =electric-quote-context-sensitive=, though, allows me to use the single 
quote, which is neither a shift nor an accent key in my keyboard, and I must 
recognize it is indeed neat.  Better than the chord the shift key would 
require.  So, this is true for all who use an US international keyboard, in 
which both the single quote and the backtick are of convenient typing.  This 
is general enough, but might not be universal.

All in all, I take back my final suggestion.  What is already in place is 
superior to what I had envisaged and suggested.

However, the cases described in the report could indeed work for electric 
quotes in a more akin fashion to other electric pairs.  If this is possible, I 
think it is still desirable.

In this respect, I've reached a temporary workaround to inhibit the pairing in 
a left word boundary (no bliss yet for del-sel though):

#+begin_src emacs-lisp
(defun my/electric-quote-inhibit-pair (orig-fun &rest args)
  (apply orig-fun args)
  (when (eq (char-syntax (following-char)) ?w); only before words.
    (pcase electric-quote-chars
      (`(,q< ,q> ,q<< ,q>>)
       (save-excursion
         (cond ((search-backward (string q>) (1- (point)) t)
                (replace-match ""))
               ((search-backward (string q>>) (1- (point)) t)
                (replace-match ""))))))))
(advice-add 'electric-quote-post-self-insert-function
            :around #'my/electric-quote-inhibit-pair)
#+end_src

I bring this because I played with different inhibit rules in the ~when~ 
clause, and had initially tried to use the same inhibit criteria as I use for 
the remaining electric pairs, that is simply using 
~electric-pair-inhibit-predicate~.  This led to some undesired behavior at the 
moment of *closing* the quotes, which did not skip as expected.  So, as far as 
I can tell, different pairing inhibit rules might be needed for electric 
quotes in particular.  For this workaround I kept only left word boundaries.


Best regards,
Gustavo Barros.


On Thu, Jun 20 2019, Gustavo Barros wrote:

> I've been using both 'electric-pair-mode' and 'electric-quote-mode' for some
> time, and they mostly come in really handy. So they are appreciated. But
> their interaction still leaves some things to be desired for: in sum,
> electric-quotes do not behave as other electric-pairs. Thus this report.
>
> I don't think I can exhaust all the cases involved in their interaction, but 
> I
> try to document some specific ones I've identified more precisely.
>
> So, in the examples bellow, I'll consider mostly two cases: quote insertion 
> on
> a left word boundary, and quote insertion on an active region. In them, I 
> use
> "|" to denote point position and "|foo|" to denote an active region.
>
> Steps followed:
>
> #+begin_src bash
> emacs -Q
> #+end_src
>
> Then:
>
> #+begin_src emacs-lisp
> (text-mode)
> (electric-pair-mode)
> (electric-quote-mode)
> (setq electric-pair-inhibit-predicate 'electric-pair-conservative-inhibit)
> #+end_src
>
> With this settings in hand, and in the following situations (as described
> above):
>
> #+begin_example
> foo |bar baz
> foo |bar| baz
> #+end_example
>
> If we type ` (one backtick), the result is:
>
> #+begin_example
> foo ‘’bar baz
> foo ‘bar’ baz
> #+end_example
>
> But the expected result would be:
>
> #+begin_example
> foo ‘bar baz
> foo ‘bar’ baz
> #+end_example
>
> Well, this is 'expected' as far as I can see. Its worth noting though that 
> it
> is the same behavior exhibited by inserting " (a double quote), thus
> independently of electric-quote. That is, the pair is inserted in the left
> boundary of 'bar' for a double quote. This happens in text-mode, but not in
> emacs-lisp-mode, code or comments, or in org-mode. The pairing in this
> position also does not happen for other electric-pair symbols, such as 
> braces,
> parentheses etc. So I don't really know if I'm missing something, and this 
> is
> expected behavior of the selected 'electric-pair-inhibit-predicate' in text
> mode, or if there is something else in play.
>
> Now, if we type `` (two backticks), we get:
>
> #+begin_example
> foo “”bar baz
> foo “”bar’ baz
> #+end_example
>
> But the expected result would be:
>
> #+begin_example
> foo “bar baz
> foo “bar” baz
> #+end_example
>
> Yet, if we further add 'delete-selection' to the bunch:
>
> #+begin_src emacs-lisp
> (delete-selection-mode)
> #+end_src
>
> If we type ` (one backtick), the result is:
>
> #+begin_example
> foo ‘’bar baz
> foo ‘’ baz
> #+end_example
>
> And, if we type `` (two backticks), we get:
>
> #+begin_example
> foo “”bar baz
> foo “” baz
> #+end_example
>
> The expectation here is that results should not be affected by
> 'delete-selection-mode'. As is the case for other electric-pair pairs.
>
>
> Well, this is the report describing the relevant behavior, that I believe 
> not
> to be expected. But, beyond that, I'd like to add a related suggestion, 
> which
> I think is pertinent to the issue at hand.
>
> The typing strategy adopted by 'electric-quote-mode' relies on the typing of
> two keys (' single quote; ` backtick), which have to be typed twice to get 
> to
> a double curved quote. (True, electric-pair can reduce this typing, but
> that's independent.)
>
> Now, the fact that double curved quotes are inserted by the sequential 
> typing
> of either key complicates their pairing in the active region case. For, as 
> is
> expected, after the first (single) quote is inserted, the region is no 
> longer
> active. There might be ways around this, I don't know.
>
> Still, making 'electric-quote-mode' (more) context-sensitive may relieve it 
> of
> the sequencial key pressing, and help solve this technical difficulty.
> E.g. on a left word boundary, insert a left curved quote; on a right word
> boundary, insert a right curved quote, and so on. Of course, the relevant
> cases would have to be thought through. And, of course, a way to force
> desired behavior in case context-sensitivity doesn't get it right would also
> have to be provided.
>
> But, in this fashion, 'electric-quote-mode' could rely on a single
> key-pressing for each kind of quote (' single quote and " double quote seem
> natural candidates), this would likely streamline curved quotes to behave in
> similar fashion as their other electric-pair relatives. In my view, it would
> also improve editing experience.
>
>
> Best regards,
> Gustavo Barros.
>
>
>
>
>
>
>
>
>
> In GNU Emacs 26.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.30)
> of 2019-04-19 built on gusbrs-laptop
> Windowing system distributor 'The X.Org Foundation', version 11.0.11906000
> System Description: Linux Mint 19.1 Tessa
>
> Recent messages:
> For information about GNU Emacs and the GNU system, type C-h C-a.
> Mark set [2 times]
> nil
> t [2 times]
> electric-pair-conservative-inhibit
> t
>
> Configured using:
> 'configure --with-mailutils --with-xwidgets --with-modules'
>
> Configured features:
> XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS GLIB
> NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
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> LIBSYSTEMD LCMS2
>
> Important settings:
> value of $LC_MONETARY: pt_BR.UTF-8
> value of $LC_NUMERIC: pt_BR.UTF-8
> value of $LANG: en_US.UTF-8
> locale-coding-system: utf-8-unix
>
> Major mode: Text
>
> Minor modes in effect:
> delete-selection-mode: t
> electric-pair-mode: t
> tooltip-mode: t
> global-eldoc-mode: t
> electric-quote-mode: t
> electric-indent-mode: t
> mouse-wheel-mode: t
> tool-bar-mode: t
> menu-bar-mode: t
> file-name-shadow-mode: t
> global-font-lock-mode: t
> font-lock-mode: t
> blink-cursor-mode: t
> auto-composition-mode: t
> auto-encryption-mode: t
> auto-compression-mode: t
> line-number-mode: t
> transient-mark-mode: t
>
> Load-path shadows:
> None found.
>
> Features:
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>
> Memory information:
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