Testing whether a mode is enabled

Testing whether a mode is enabled

[Heime via Users list for the GNU Emacs text editor]

Am using icomplete-mode but find things somewhat confusing.

To enable or disable the mode one uses (icomplete-mode 1) and (icomplete-mode -1)

I want to test whether the mode is enabled or disabled with "(if icomplete-mode" and
(if (not icomplete-mode)".

(not OBJECT) returns t if OBJECT is nil, and returns nil otherwise.

When I use conditional with "icomplete-mode" is it correct to say that if "icomplete-mode" is nil,
then the mode is disabled?

I am uncertain because of the numeric values used to enable and disable.

Re: Testing whether a mode is enabled

[Michael Heerdegen]

Heime via Users list for the GNU Emacs text editor
<help-gnu-emacs@gnu.org> writes:

> I am uncertain because of the numeric values used to enable and disable.

The variable has a docstring.  This is the crucial source for you.
Nearly all mode variables are interpreted as Bools in Emacs.

The argument of the mode functions is different because it is often also
the prefix arg, which is a number (not even only just that, actually).
But it can also be called from Elisp.  That's why its semantics are a
bit ugly.

Michael.

Re: Testing whether a mode is enabled

[Heime]

Sent with Proton Mail secure email.

------- Original Message -------
On Sunday, October 16th, 2022 at 11:15 PM, Michael Heerdegen <michael_heerdegen@web.de> wrote:


> Heime via Users list for the GNU Emacs text editor
> help-gnu-emacs@gnu.org writes:
> 
> > I am uncertain because of the numeric values used to enable and disable.
> 
> 
> The variable has a docstring. This is the crucial source for you.
> Nearly all mode variables are interpreted as Bools in Emacs.

I see.  Which is either t or nil in the docstring.
 
> The argument of the mode functions is different because it is often also
> the prefix arg, which is a number (not even only just that, actually).
> But it can also be called from Elisp. That's why its semantics are a
> bit ugly.
> 
> Michael.

Not trivial.