Happy Flag Day

[Bernard S. Greenberg <BSG at SCRC-TENEX>]

Re: Consistency of if/if-not's: I would like to quote the 
following excerpts from the laser manual:

(p. 182) 
SUBST new old tree &key :test :test-not :key
SUBST-IF predicate new tree &key :key
SUBST-IF-NOT predicate new tree &key :key

NSUBST new old tree &key :test :test-not :key
NSUBST-IF predicate new tree &key :key
NSUBST-IF-NOT predicate new tree &key :key

(p. 166)
SUBSTITUTE newitem olditem sequence &key :from-end ...
SUBSTITUTE-IF newitem test sequence &key ...
SUBSTITUTE-IF-NOT newitem test sequence &key ...

NSUBSTITUTE newitem olditem sequence &key :from-end ...
NSUBSTITUTE-IF newitem test sequence &key ...
NSUBSTITUTE-IF-NOT newitem test sequence &key ...


Either SUBSTITUTE-IF and his minions are consistent, as according to
Steele and Moon, because the predicate replaces the "old" argument, but
SUBST-IF and friends are inconsistent because of historical
considerations, OR SUBST-IF and friends are consistent with all of the
others (not shown here), because the predicate argument is first in all
of them, and SUBSTITUTE-IF and friends are inconsistent because they are
wrong.