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smoking things out of macsyma

I really doubt that all problems are simple
to smoke out;  in fact, I suspect that there are still places
where the Lisp Machine version of Macsyma fails for mysterious
reasons.  These may be totally unrelated to T vs #T or NIL vs (),
but I do not see how GJC can be so confident.

For example, when we brought Macsyma up on the VAX, (after it
had allegedly been brought up on a CADR) we found
places where property lists were found by computing CAR of atoms;
we found a number of cases of (not)working-by-accident functions whose
non-functionality was noticed only when run on the VAX with a modest
amount of additional error checking. (e.g. programs which should
have bombed out just chugged along on the pdp-10).

GJC claims there is (was?) only one line of Macsyma which legally
depends on other-than truthity of a predicate. I believe this is
false, but in any case, a  proof of his claim would require rather
extensive analysis. Whichever way this decision goes (about NIL or ()),
I would be leery of making too much of GJC's note for supporting evidence.