Re: About how misspelled word are displayed

[N. Raghavendra]

At 2017-05-12T10:32:36-07:00, Drew Adams wrote:

> If you are not the one who defined a given defcustom,
> and if that defcustom uses a keyword such as :set, then a
> complicated beast has likely been created for you already.
>
> If you try to tame that beast without taking its nature
> into account (e.g., using just `setq') you can find
> yourself surprised.

I was curious about examples of such options, that is, of options for
which (setq option ...) and (customize-set-variable 'option ...) have
different effects.  The option `minibuffer-prompt-properties' is one
such, as described in

http://xahlee.blogspot.in/2016/06/emacs-custom-set-variables-vs-setq.html

and

http://ergoemacs.org/emacs/emacs_stop_cursor_enter_prompt.html

If I do

emacs -Q --eval "(setq minibuffer-prompt-properties (append '(cursor-intangible 
t) minibuffer-prompt-properties))"

and type `M-x query-replace' and start pressing the left arrow key,
point goes over the prompt "M-x".

On the other hand, if I do

emacs -Q --eval "(customize-set-variable 'minibuffer-prompt-properties (append 
'(cursor-intangible t) minibuffer-prompt-properties))"

and type `M-x query-replace' and start pressing the left arrow key,
point is prevented from entering the prompt "M-x", and stops at the
letter "q" of the command name "query-replace".

Thus, (setq minibuffer-prompt-properties ...) and
(customize-set-variable 'minibuffer-prompt-properties ...) have
different effects.  The reason, as pointed out by Clément Pit-Claudel in
a comment at the second URL above, is that the :set function of
minibuffer-prompt-properties does an

(add-hook 'minibuffer-setup-hook 'cursor-intangible-mode)

when the value being assigned is a list containing the symbol
`cursor-intangible'.

Raghu.

--
N. Raghavendra <raghu@hri.res.in>, http://www.retrotexts.net/
Harish-Chandra Research Institute, http://www.hri.res.in/