On Sun, Jul 24, 2022 at 01:42:14PM +0200, carlmarcos@tutanota.com wrote:
> Jul 24, 2022, 11:26 by tomas@tuxteam.de:
> 
> > On Sun, Jul 24, 2022 at 01:12:39PM +0200, carlmarcos--- via Users list for the GNU Emacs text editor wrote:
> >
> > [...]
> >
> >> I'd appreciate if emacs could provide a minimum set of functions to manipulate list,
> >> as string manipulations are of good use.
> >>
> >
> > Why do you always refuse to read the docs?
> >
> >> What can be introduced, you think?
> >>
> >
> > What is missing, from your point of view?
> >
> What can I use to test whether a string in composed of whitespace or is empty?

Try (string-match-p "^[[:space:]]*$" your-string-here)

If you want it to only match "horizontal white space" (i.e. no newlines,
no vertical tabs), try :blank: instead.

Cheers
-- 
t