status: Passed, as amended, Jan 89 X3J13
Note: some confusion in minutes as to whether COMPLEMENT was added
as part of TEST-NOT-IF-NOT or whether FUNCTION-COMPOSITION was
passed but with only COMPLEMENT preserved.
In any case: TEST-NOT-IF-NOT:FLUSH-ALL as stated here
passed with "Remove" -> "Deprecate". See issue
FUNCTION-COMPOSITION for more details.
References: Functions offering a :TEST-NOT keyword:
ADJOIN (p276), ASSOC (p280), COUNT (p257), DELETE (p254),
DELETE-DUPLICATES (p254), FIND (p257),
INTERSECTION (p277), MEMBER (p275), MISMATCH (p257),
NINTERSECTION (p277), NSET-DIFFERENCE (p278),
NSET-EXCLUSIVE-OR (p278), NSUBLIS (p275), NSUBST (p274),
NSUBSTITUTE (p256), NUNION (p276), POSITION (p257),
RASSOC (p281), REMOVE (p253), REMOVE-DUPLICATES (p254),
SEARCH (p258), SET-DIFFERENCE (p278),
SET-EXCLUSIVE-OR (p278), SUBLIS (p274), SUBSETP (p279),
SUBST (p273), SUBSTITUTE (p255), TREE-EQUAL (p264),
Functions with "-IF-NOT" in their name:
ASSOC-IF-NOT (p280), COUNT-IF-NOT (p257),
DELETE-IF-NOT (p254), FIND-IF-NOT (p257),
MEMBER-IF-NOT (p275), NSUBST-IF-NOT (p274),
NSUBSTITUTE-IF-NOT (p256), POSITION-IF-NOT (p257),
RASSOC-IF-NOT (p281), REMOVE-IF-NOT (p253),
SUBST-IF-NOT (p273), SUBSTITUTE-IF-NOT (p255);
Related Issue: FUNCTION-COMPOSITION
Edit history: 02-Oct-88, Version 1 by Pitman (just FLUSH-ALL)
05-Oct-88, Version 2 by Pitman (add option FLUSH-TEST-NOT)
01-Dec-88, Version 3 by Masinter (add discussion)
18-Mar-89, Version 4 by Masinter (as amended)
The -IF-NOT functions are functionally unnecessary.
The :TEST-NOT keywords are not only functionally unnecessary but
also problematic because it's not clear what to do when both :TEST
and :TEST-NOT are provided.
Many people think Common Lisp is more `bloated' than it needs
to be and these aspects of the language are commonly cited
Deprecate all -IF-NOT functions (named above) from Common Lisp.
Deprecate the :TEST-NOT keyword from the Common Lisp functions which
currently provide them (named above).
This makes the language a bit simpler.
The removal of :TEST-NOT also makes the language easier to explain.
Cost to Implementors:
Some symbols would disappear from the LISP package but could
still be offered in proprietary packages if deemed important
Implementations could compatibly retain the :TEST-NOT keywords
for an interim period.
Presumably no one has done this yet.
Cost to Users:
Some rewrites would be needed.
Those rewrites, which are already fairly simple, would be even
more simple if some form of the FUNCTION-COMPOSITION issue is
voted in -- in particular, the COMPLEMENT function which it
proposes would help enormously in this regard.
Cost of Non-Adoption:
Common Lisp would continue to be what some people feel is
"bigger than it needs to be".
The cost of non-adoption would be avoided.
Presumably this makes the language easier to teach.
Very small; removing the :TEST-NOT keywords would
make the simple implementation of the functions that
used to have them slightly faster, but the resulting
code of the inner loop is likely to be much slower.
Many people objected strongly to this proposals --
they might have been a nice idea five years ago, but are
gratuitous incompatibilities now: incompatible changes with
Some of those objections might be tempered if some additional
changes were made to Common Lisp: adding a COMPLEMENT
function, or if there were a strategy to declare some parts of the
language "obsolete". Since these conditions haven't been done,
their objections stand.
Steele noted that one main reservation to FLUSH-ALL is that
he uses REMOVE-IF-NOT much more than REMOVE-IF.
This issue is related to FUNCTION-COMPOSITION, but is not
dependent on it. Some support the combination of FLUSH-ALL and
the NEW-FUNCTIONS part of FUNCTION-COMPOSITION in spite of
the incompatible change because of the aesthetic appeal.
Some people expressed their intention to vote for FLUSH-ALL
only if FUNCTION-COMPOSITION:NEW-FUNCTIONS.
It was noted that and
adding a #~ readmacro such that
(FIND-IF-NOT #'ZEROP '(0 0 3))
== (FIND-IF (COMPLEMENT #'ZEROP) '(0 0 3))
== (FIND-IF #~ZEROP '(0 0 3))
The modification of these functions is moot for those who
prefer to use extended LOOP macro/iteration constructs
in lieu of the sequence functions.
Several alternative names for REMOVE-IF-NOT were
suggested: KEEP-IF, ABSTRACT, FILTER. We did not
pursue these suggestions.