Re: wid-edit.el

[Per Abrahamsen]

Kazu Yamamoto (山本和彦) <kazu@iijlab.net> writes:

> I have a question about wid-edit.el contained in Emacs 21.
>
> I'm using one Elisp package which requires wid-edit.el even when Emacs
> 21 is executed with the "-nw" option. Since wid-edit.el is using
> the create-image fuction, it loads "image.el". 

The glyph code for Emacs was added long after I handed over
'wid-edit.el' to the FSF, so I know very little about it.  I have CC'ed
to <bug-gnu-emacs@gnu.org>.

> My goal is to avoid loading "image.el" when "-nw". Would you suggest
> me which one is a right way?
>
> (1) Packages should not require wid-edit.el if Emacs 21 is executed
>     the "-nw" option.

The "wid-edit" functions _ought_ to be autoloaded when used, so it
_ought_ to be unnecessary to explicitly load it.  However, whether
this theory holds I'm not sure of.

> (2) It is OK for packages to require wid-edit.el in any cases. 

It should be.

> So,
>
>     (2.0) The current code of wid-edit.el is correct. "image.el" is
>           meaningful even with "-nw".

Does it do any harm?  'image.el' appears to be a rather small file.

>     (2.1) wid-edit.el should avoid loading "image.el" and should be
>           modified to implement this.
>
>     (2.3) wid-edit.el should avoid loading "image.el", however, to
>           make code simple, the current coding style was chosen.

Maybe, the problem seem to be the 'checkbox' widget call
'create-image' for :on-glyph and :off-glyph.  These calls could be
"lazy evaled" to delay the actual creation, but it would complicate
the code.  I have no opinion on whether that would be worthwhile.