Stop highlighting parentheses when I start typing

Question

I use (show-paren-mode 1) to get help seeing where parentheses are. I have (setq show-paren-delay 2) to prevent intrusive highlighting when I don't need it. This is how it works now:

1. Put cursor on a parenthesis. After 2 seconds, both parentheses highlight
2. Use cursor keys. Highlighting stays on as long as I keep cursoring.
3. Stop moving around. Highlighting eventually disappears, after 2 seconds.

It should work like this:

1. Same as above.
2. Use cursor keys. Highlighting disappears immediately!

The rationale is that I need highlighting as an aide to find the matching parenthesis, or to detect imbalance. Once I've established this, the highlighting is no longer useful and I want it gone.

Answer 1

It should work like this: [...] Use cursor keys. Highlighting disappears immediately!

I want show-paren-delay only when navigating the code. If I actually type a new parenthesis, I want immediate highlighting.

You can make it work like that with the following code. show-paren-clear-highlight should be added to Emacs since it's accessing internal variables.

(defun show-paren-clear-highlight ()
  "Turn off any previous paren highlighting."
  (delete-overlay show-paren--overlay)
  (delete-overlay show-paren--overlay-1))

;; Instead of relying on `delsel', you could use
;; `before-change-functions' to detect insertions.  That might be more
;; reliable, but also more complicated.
(require 'delsel)
(defun my-show-paren-update-on-insert ()
  ;; A command with `delete-selection' property probably inserts text.
  (if (get this-command 'delete-selection)
      (show-paren-function)
    (show-paren-clear-highlight)))

(add-hook 'post-command-hook #'my-show-paren-update-on-insert)