bug#62536: 30.0.50; Can we add """ ... """ electric pair in elixir, just like python

[Wilhelm Kirschbaum <wkirschbaum@gmail.com>]

> Wilhelm Kirschbaum <wkirschbaum@gmail.com> writes:
>
>>>> And in electric-layout-rules you _can_, I think, identify
>>>> triple quotes using a function as described in the last
>>>> paragraph of its docstring.
>>>>
>>> Yes, I tested this earlier and it does work.
>>>
>>
>> Even though it works, it does not play nice with the custom 
>> psif,
>> because the layout rules seems to trigger before the hook.
>
> There could yet be a snag here, which I didn't anticipate, which 
> is that
> rules in electric-layout-rules do not trigger if inside strings 
> or
> comments, and that is hardcoded.
>
> Let's assume we got rid of the snag or had some mechanism to 
> override
> it:
>
>     diff --git a/lisp/electric.el b/lisp/electric.el
>     index bac3f5a2b3c..cef5326852c 100644
>     --- a/lisp/electric.el
>     +++ b/lisp/electric.el
>     @@ -409,9 +409,7 @@ 
>     electric-layout-post-self-insert-function-1
>                                      (goto-char pos)
>                                      (funcall probe 
>                                      last-command-event))))
>                               (when res (throw 'done 
>                               res))))))))))
>     -    (when (and rule
>     -               ;; Not in a string or comment.
>     -               (not (nth 8 (save-excursion (syntax-ppss 
>     pos)))))
>     +    (when rule
>            (goto-char pos)
>            (when (functionp rule) (setq rule (funcall rule)))
>            (dolist (sym (if (symbolp rule) (list rule) rule))
>
>
> Then, the following simple patch seems to have good results in 
> my tests.
>
>    (defun joaot/looking-back-at-exactly-three-quotes-p ()
>      (looking-back "\\(\\`\\|[^\"]\\)\"\"\"" (- (point) 4)))
>     
>    (defun joaot/triple-quotes ()
>      (when (and (eq ?\" last-command-event)
>                 (joaot/looking-back-at-exactly-three-quotes-p))
>        (save-excursion (insert "\"\"\"" ))))
>     
>    (defun joaot/layout-after-triple-quotes (inserted)
>      (when (and (eq inserted ?\") 
>      (joaot/looking-back-at-exactly-three-quotes-p))
>        '(after-stay after)))
>     
>    (defun joaot/setup-elixir-electricity ()
>      (electric-layout-local-mode 1)
>      (electric-pair-local-mode 1)
>      (electric-indent-local-mode 1)
>      (add-hook 'post-self-insert-hook 
>      'joaot/super-quotes-and-newlines -05 t)
>      (setq-local electric-layout-rules
>                  (list #'joaot/layout-after-triple-quotes)))
>     
>    (add-hook 'elixir-ts-mode-hook 
>    'joaot/setup-elixir-electricity)
>
> João

Thanks, yes.  I think this brings us closer.  For some more fun, 
and the
other part of the issue I have not mentioned is this scenario:

```elixir
def foo() do
  ~H"""
  <foo class=
  """
end
```

then completing `class=""` jumps into the end of the template , 
which is
pretty annoying, more so that the current issue at hand.

The other patch in this thread will porpertize the `"""` as
`$` for a lack of a better syntax class, which then breaks it 
again and
produces:

```
"""
|"
"""
```

the highlight the propertize function change:

@ -550,6 +552,22 @@ elixir-ts--defun-name
                 (_ nil))))
     (_ nil)))
 
+(defvar elixir-ts--syntax-propertize-query
+  (when (treesit-available-p)
+    (treesit-query-compile
+     'elixir
+     '(((["\"\"\""] @quoted-text))))))
+
+(defun elixir-ts--syntax-propertize (start end)
+  "Apply syntax text properties between START and END for 
`elixir-ts-mode'."
+  (let ((captures
+         (treesit-query-capture 'elixir 
elixir-ts--syntax-propertize-query start end)))
+    (pcase-dolist (`(,name . ,node) captures)
+      (pcase-exhaustive name
+        ('quoted-text
+         (put-text-property (1- (treesit-node-end node)) 
(treesit-node-end node)
+                            'syntax-table (string-to-syntax 
"$")))))))
+
 ;;;###autoload
 (define-derived-mode elixir-ts-mode prog-mode "Elixir"
   "Major mode for editing Elixir, powered by tree-sitter."
@@ -630,7 +648,8 @@ elixir-ts-mode
                     ( elixir-sigil elixir-string-escape
                       elixir-string-interpolation ))))
 
-    (treesit-major-mode-setup)))
+    (treesit-major-mode-setup)
+    (setq-local syntax-propertize-function 
#'elixir-ts--syntax-propertize)))