Re: Faces customization group linked from mode groups

[Juri Linkov]

> To my surprise the suitable link type is already implemented but not
> documented.  The name of such one-way link type is `custom-group-link'.

There are more undocumented link types:

find . -type f -print0 | xargs -0 -e grep -inH -e "define-widget.*link"
./cus-edit.el:1655:(define-widget 'custom-manual 'info-link
./cus-edit.el:3470:(define-widget 'custom-group-link 'link
./wid-edit.el:1737:(define-widget 'link 'item
./wid-edit.el:1747:(define-widget 'info-link 'link
./wid-edit.el:1757:(define-widget 'url-link 'link
./wid-edit.el:1767:(define-widget 'function-link 'link
./wid-edit.el:1777:(define-widget 'variable-link 'link
./wid-edit.el:1787:(define-widget 'file-link 'link
./wid-edit.el:1797:(define-widget 'emacs-library-link 'link
./wid-edit.el:1807:(define-widget 'emacs-commentary-link 'link
./wid-edit.el:2800:(define-widget 'documentation-link 'link

>From all these link types only four are documented in the Emacs Lisp
manual in the node (info "(elisp)Common Keywords"): custom-manual,
info-link, url-link and emacs-commentary-link.  What about documenting
remaining six types: custom-group-link, function-link, variable-link,
file-link, emacs-library-link and documentation-link?  Maybe
Widget link types should be documented in the Widget manual, and
the Emacs Lisp manual should have a cross reference from
(info "(elisp)Common Keywords") to (info "(widget)Basic Types")?

Also the docstring of `defcustom' documents only three link types.
I'm not sure about duplicating full descriptions from the manual,
but at least the docstring could mention all available link types.

-- 
Juri Linkov
http://www.jurta.org/emacs/