cape and boundaries (was: typing slows down dramatically when typing digits in emails)

[Stefan Monnier via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

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Eric S Fraga [2022-12-22 10:22:29] wrote:
> On Wednesday, 21 Dec 2022 at 23:09, Stefan Monnier via Users list for the
> GNU Emacs text editor wrote:
>>>         5311  79%             - completion-boundaries
>>>         5311  79%              - #<compiled 0x1f4100e4f6213ad7>
>>>         5311  79%               - complete-with-action
>>>         5311  79%                - #<compiled 0xfe6876f217f45e4>
>>>         4776  71%                 - cape--dabbrev-list
>>>         4776  71%                  - dabbrev--find-all-expansions
>>>         4704  70%                   - dabbrev--find-expansion
>>>         4671  70%                    - dabbrev--try-find
>>>         2959  44%                     - dabbrev--search
>>
>>`completion-boundaries` should not need to perform a `dabbrev--search`.
>> Which version of Emacs is that?
>
> It's Emacs from git, up to date as of yesterday morning.
>
>> It would be useful to figure out what is this
>> #<compiled 0x1f4100e4f6213ad7> function (presumably a completion-table)
>> and how it calls `complete-with-action` because normally it should call
>> it with an argument of the form `(boundaries . N)` which should cause
>> `complete-with-action` to return nil immediately.
>
> Any suggestion on how to do this?  I guess I would need to disable
> native compilation and re-build?

Oh, I forgot that `complete-with-action` actually won't return immediately
if the completion table it's passed as argument is itself a function.
I'm not sure if the patch below will make much difference (there's
a chance the `dabbrev--search` will still take place, just via some
other call), but at least I think it's "Right".

Daniel, WDYT?


        Stefan

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diff --git a/cape.el b/cape.el
index dfb1e7a95c..f10decb5ff 100644
--- a/cape.el
+++ b/cape.el
@@ -199,13 +199,17 @@ VALID is the input comparator, see `cape--input-valid-p'."
         (end (copy-marker end t))
         (table nil))
     (lambda (str pred action)
-      (let ((new-input (buffer-substring-no-properties beg end)))
-        (when (or (eq input 'init) (not (cape--input-valid-p input new-input valid)))
-          ;; NOTE: We have to make sure that the completion table is interruptible.
-          ;; An interruption should not happen between the setqs.
-          (setq table (funcall fun new-input)
-                input new-input)))
-      (complete-with-action action table str pred))))
+      (if (or (eq action 'metadata) (eq (car-safe action) 'boundaries))
+          nil
+        (let ((new-input (buffer-substring-no-properties beg end)))
+          (when (or (eq input 'init)
+                    (not (cape--input-valid-p input new-input valid)))
+            ;; NOTE: We have to make sure that the completion table is
+            ;; interruptible.  An interruption should not happen
+            ;; between the setqs.
+            (setq table (funcall fun new-input)
+                  input new-input)))
+        (complete-with-action action table str pred)))))
 
 ;;;; Capfs