Feature-request for Customize, delayed evaluation

[squash@math.ufl.edu (Jonathan LF King)]

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Dear Emacs

  Often I'd like to customize a variable to a value making use of
  another variable, e.g to set

  outgoing-mail-file
to
 (concat mail-dir (current-date) ".mail")
 .

Currently, Customize evaluates this and sets `outgoing-mail-file' to 
	"~squash/Missives/13Jan2004.mail"
and ALSO puts that value in the .emacs file.

If, in a future session, I alter mail-dir, then outgoing-mail-file
will be wrong.

Request:  Under the STATE button of Customize is the option

	Save for Future Sessions

Would it be possible to have *two* options:

	Save value for Future Sessions
and
	Save expression for Future Sessions and evaluate now

The latter creates, in .emacs, this expression:


  (custom-set-variables
   ...
   '(outgoing-mail-file (concat mail-dir (current-date) ".mail") ...)
  ...
  )

but immediately binds 

	outgoing-mail-file 
to 
	"~squash/Missives/13Jan2004.mail".


Sincerely,   -Prof.  Jonathan King


PS:  If you post a reply, I'd appreciate your CCing me as my
news-feed is unreliable.  Thank you.


-- 
Prof. Jonathan LF King	  Mathematics dept, Univ. of Florida
<squash@math.ufl.edu>,	  <http://www.math.ufl.edu/~squash/>