Is Customize's UI separated from the backend?

Is Customize's UI separated from the backend?

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

Just wondering: if someone wants to create an alternative Customize UI (e.g. if GTK is compiled in then popping up a GTK dialog box with GTK widgets) then is the UI part in Customize separated from the backend, so it's only a matter of reimplementing the UI calls or is the whole thing engtangled right now?

FW: [External] : Is Customize's UI separated from the backend?

[Drew Adams]

Forwarding to the list.  Bitten by the "Reply All"
doesn't work when replying to some (a couple) users.

-----Original Message-----
Sent: Sunday, April 11, 2021 2:34 PM
To: 'scame' <laszlomail@protonmail.com>

> Just wondering: if someone wants to create an alternative Customize UI (e.g.
> if GTK is compiled in then popping up a GTK dialog box with GTK widgets) then
> is the UI part in Customize separated from the backend, so it's only a matter
> of reimplementing the UI calls or is the whole thing engtangled right now?

Pretty much, separate, yes.  Just call the relevant
functions, to change values, save them, revert to
backed-up values (or standard values), etc.

This page I wrote a while ago might help with some
of the understanding:

https://www.emacswiki.org/emacs/CustomizingAndSaving

As for UIs for visually changing things, e.g.
incrementally, which you can then save (or not),
this page may help with that, at least as food for
thought:

https://www.emacswiki.org/emacs/DoReMi

Icicles also offers direct manipulation for changing
options and faces.  Like Do Re Mi it lets you change
things incrementally, but you can also use completion.

https://www.emacswiki.org/emacs/Icicles

And Facemenu and FacemenuPlus can also help change
settings (which you can then save).

https://www.emacswiki.org/emacs/FaceMenuPlus

I encourage people designing and implementing more
and better UIs for _direct manipulation_ of UI
appearance and behavior (settings).  These libraries
can hopefully serve as some food for thought.

Emacs has a lot you can use to do things differently,
or better, than what it offers out of the box.
Unfortunately, the Custom code (e.g. custom.el and
cus-*.el) is hard to fathom.  It's not one of the
easiest interfaces for "asking Emacs" itself, as
you may have already discovered.