Proposed incompatible change to MacLISP FORMAT function

["Guy L. Steele, Jr." <GLS at MIT-MC>]

    Date: 16 JUN 1979 0323-EDT
    From: RWK at MIT-MC (Robert W. Kerns)

From:         Date:
Date: Thu, 15 Jun 79 23:44:18 GMT
Original-Date: 06/15/79 19:44:18 EDT
Subject:
        From: GLS at MIT-AI
        To:   *CMU, *DM, *MC, *ML, *AI
        Re:   Proposed incompatible change to MacLISP FORMAT function

        Currently NIL means "output to the standard output files" (under the
        control of TYO, OUTFILES, ^W, and ^R variables), and T means "output
        to the file in the TYO variable".  ... to get what NIL now means, one
        can use T. To get what T now means, one can use a list of T, i.e. (T).
        Any objections?
        -- GLS

    What's wrong with using TYO to mean "output to the file in the TYO variable"?
    (For that matter, why not call TYO something LISPM compatible like
    CONSOLE-OUTPUT?  It's probably too late, but calling the variable TYO was a
    mistake, I think.)  I have never used T to mean TYO, I always use TYO directly,
    so this won't break any of my code on that score, although maybe the NIL might.

    However, I think this change is important enough to change to make it worth
    fixing the various code which will be broken.  (JONL:  No cracks about fixing
    DRB's modes package, please!)
I forgot to mention that T means "use the value in TYO, UNDER
THE CONTROL OF THE ^W SWITCH".  Hence (FORMAT '(T) ...) and
(FORMAT TYO ...) would mean slightly different things.