[no subject]

[GLS at MIT-MC (Guy L. Steele, Jr.)]

    Date: 19 JUN 1978 0730-EDT
    From: KMP at MIT-MC (Kent M. Pitman)
    To: (BUG LISP) at MIT-MC

    It would probably be a win if SORT would not set the thing you pass it until
    it knows if the predicate you have given it wins.
    Case in point:
    (SETQ I (SORT I 'ALPHLESSP))
    ;ALPHLESSP UNDEFINED FUNCTION OBJECT
    ;BKPT UDF-FNC-OBJ
    ^G
    QUIT
    I
    (B)
    Apparently you immediately have the thing passed get re-assigned in some
    way, but could you leave the original list intact until at least one check
    is done? (If this would be grossly inefficient, then don't worry about it,
    but if it is not, then you would probably save some people like me occasional
    grief - I expect it to clobber my list, but that's ok if I have new list to
    play with -- in this case however am left with nothing -- yes, i should have
    defined the function while in the breakpoint, but I didn't think I would
    get scrod if I just aborted and started over spelling it right. Sigh.)
    --kmp
The answer is that if you aren't sure, you should make a copy of
the list ifrst.