bug#36309: 26.2; Interaction between electric-pair and electric-quote

[Gustavo Barros]

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

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