[COMSAT: Msg of Tuesday, 15 January 1985 16:51-EST]

[Jonathan A Rees <JAR@MIT-MC>]

Date: 19 January 1985 08:06-EST
From: Communications Satellite <COMSAT>
To:   JAR
Re:   Msg of Tuesday, 15 January 1985 16:51-EST

FAILED: T-Users at YALE; Host appears to be permanently down or not accepting mail.
 Failed message follows:
-------
Date: 15 January 1985 16:51-EST
From: Jonathan A Rees <JAR @ MIT-MC>
Subject:  bound?
To: rosen @ UCLA-LOCUS
cc: T-Users @ YALE
In-reply-to: Msg of Mon 14 Jan 85 00:31:12 PST from Bruce E. Rosen <rosen at UCLA-LOCUS.ARPA>

    Date: Mon, 14 Jan 85 00:31:12 PST
    From: Bruce E. Rosen <rosen at UCLA-LOCUS.ARPA>

    One of the reasons I use BOUND? is that I frequently redefine system
    functions for my own use.  I want to save the system function under a
    new name.  I check if that name is bound.  If it is not, then I can
    redefine the system function.  If the name is already bound, that
    means I have already saved the old definition, and I should not save
    the system function under that name.

To do this kind of thing, you shouldn't have to write load-time
conditionalizations.  To get at the value of the original system
variable, use (*VALUE *STANDARD-ENV* 'name) instead of name so that
you won't get screwed when reloading.  E.g.

(DEFINE STANDARD-CONS
  (*VALUE *STANDARD-ENV* 'CONS))

(DEFINE (CONS A B)
  (FORMAT T "A pair is being formed from ~S and ~S.~%" A B)
  (STANDARD-CONS A B))

If this doesn't solve your problem, or if you think of another
application for BOUND?, let me know.

Jonathan