[no subject]

[JONL at MIT-MC (Jon L White)]

I'D LIKE TO MAKE LAST DO THE "ATOM" TEST RATHER THAN THE "NULL" TEST,
UNLESS THRE IS A GREAT HUE AND CRY ABOUT THE **NECESSITY** FOR SPEED
IN "LAST".  PUTTING IN THE CHECKS CHANGES THE TIMING FROM  1.12 US/NODE
TO ABOUT 2.92 US/NODE, ON THE MC MACHINE.  IF THIS IS, FOR SOME REAL
REASON, UNACCEPTABLE, THEN PERHAPS WE COULD DEFINE A FAIL-SAFE FUNCTION
"LASTNODE" THAT DOES THE "ATOM" CHECK.  EITHER WAY, ALL THE OTHER
FUNCTIONS, SUCH AS APPEND, NCONC, ETC. COULD, IN *RSET MODE, MERELY
CHECK (AND (OR (ATOM ARG) (CDR (LAST ARG))) (ERROR '|NON-LIST - | ...))
BEFORE FALLING INTO THE FAST LOOP.  NOTE, HOWEVER, THAT THERE MUST
BE SOME USER-AVAILABLE FUNCTION, WHICH IS NOT AFFECTED BY *RSET, FOR
TESTING THE "NORMALITY" OF A LIST.