Re: help-echo in Custom

[Luc Teirlinck <teirllm@dms.auburn.edu>]

Since at least one of the things I described seems to be a bug, here
is a test case anyway.

Load:

===File ~/helpfun.el========================================
(defvar silly-string "Silly string")

(defun silly-help (win obj pos)
  "Used as help-echo for debugging purposes."
  (format "%s %s %s" win obj pos))

(defun silly-custom-help (widget)
  (substring (format "%s" widget) 0 70))

(defcustom silly-string-var 7
  "*This is a silly variable"
  :type '(integer :help-echo silly-string)
  :group 'convenience)

(defcustom silly-help-var 7
  "*This is an silly variable"
  :type '(integer :help-echo silly-help)
  :group 'convenience)

(defcustom silly-custom-help-var 7
  "*This is a silly variable"
  :type '(integer :help-echo silly-custom-help)
  :group 'convenience)
============================================================

Do "M-x customize-group convenience" and start <tab>-ing around.

`silly-string-var' will not display "Silly string" after <tab>,
although it will on mouse-over.  This seems to be definitely a bug and
is trivial to fix by adding two eval's, as I pointed out in my
original message.

`silly-help-var' produces a "Wrong number of arguments" error when
<tab> gets there, even though `silly-help' works perfectly as a
help-echo text or overlay property.  Maybe not a bug, but pretty
confusing, since the Elisp manual clearly suggests that my function
needs to have three arguments.

`silly-custom-help-var' displays the silly help string I wanted it to
display.  Maybe this is actually a useful feature, but if so, where is
it documented and why does the Elisp manual not refer to that place,
or, better, document it itself?

Sincerely,

Luc.