Re: predicate group-p to see if a group exists?

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Granted, most users of `defgroup', `defcustom', and `defface' will not need
> to test whether a given group exists, but some will. I still have the
> question whether we shouldn't have a function `group-p'.

IIRC I've looked into it at some point.  The problem is that currently,
the data necessary to write custom-group-p is absent.

`customize-read-group' uses the following predicate for completion
purposes:

                     (lambda (symbol)
                       (or (and (get symbol 'custom-loads)
                                (not (get symbol 'custom-autoload)))
                           (get symbol 'custom-group)))

So we could use the above as the definition of custom-group-p, but IIRC
it's not 100% reliable/correct, and the lack of comments explaining why
we check (and (get symbol 'custom-loads) (not (get symbol 'custom-autoload)))
is also a significant problem.


        Stefan