Re: behavior of '-'

KY> Hi, KY> KANEMATSU Daiji <kanematu(a)sra.co.jp&gt; reported in xemacs-beta-ja that KY> there is a bug in the byte-compiled math function under XEmacs 21.2 KY> as follows: Thanks for finding this bug. I prefer the following fix, which also adds some tests to the test suite: Index: lisp/ChangeLog =================================================================== RCS file: /usr/CVSroot/XEmacs/xemacs/lisp/ChangeLog,v retrieving revision 1.156.2.533 diff -u -w -U0 -r1.156.2.533 ChangeLog --- lisp/ChangeLog 2001/03/16 10:37:29 1.156.2.533 +++ lisp/ChangeLog 2001/03/23 07:33:30 ＠＠ -0,0 +1,5 ＠＠ +2001-03-23 Martin Buchholz <martin(a)xemacs.org&gt; + + * byte-optimize.el (byte-optimize-minus): + Fix mis-byte-compilation of (- 0 x) --> (- (- x)) + Index: tests/ChangeLog =================================================================== RCS file: /usr/CVSroot/XEmacs/xemacs/tests/Attic/ChangeLog,v retrieving revision 1.1.2.86 diff -u -w -U0 -r1.1.2.86 ChangeLog --- tests/ChangeLog 2001/03/15 16:28:54 1.1.2.86 +++ tests/ChangeLog 2001/03/23 07:33:50 ＠＠ -0,0 +1,10 ＠＠ +2001-03-23 Martin Buchholz <martin(a)xemacs.org&gt; + + * automated/lisp-tests.el: + Add test for mis-byte-compilation of (- 0 x). + +2001-03-14 Martin Buchholz <martin(a)xemacs.org&gt; + + * automated/hash-table-tests.el: + Add test with maphash mapping function calling puthash. + Index: tests/automated/lisp-tests.el =================================================================== RCS file: /usr/CVSroot/XEmacs/xemacs/tests/automated/Attic/lisp-tests.el,v retrieving revision 1.1.2.22 diff -u -w -r1.1.2.22 lisp-tests.el --- tests/automated/lisp-tests.el 2000/12/28 10:19:00 1.1.2.22 +++ tests/automated/lisp-tests.el 2001/03/23 07:33:54 ＠＠ -243,6 +243,8 ＠＠ (Assert (= (- one) -1)) (Assert (= (- one one) 0)) (Assert (= (- one one one) -1)) + (Assert (= (- 0 one) -1)) + (Assert (= (- 0 one one) -2)) (Assert (= (+ one 1) 2)) (dolist (zero '(0 0.0 ?\0)) (Assert (= (+ 1 zero) 1)) Index: lisp/byte-optimize.el =================================================================== RCS file: /usr/CVSroot/XEmacs/xemacs/lisp/byte-optimize.el,v retrieving revision 1.5.2.17 diff -u -w -r1.5.2.17 byte-optimize.el --- lisp/byte-optimize.el 2001/01/15 13:42:45 1.5.2.17 +++ lisp/byte-optimize.el 2001/03/23 07:34:10 ＠＠ -729,9 +729,15 ＠＠ (decf (nth 1 form) last) (butlast form)) - ;; (- 0 x ...) --> (- (- x) ...) - ((and (eq 0 (nth 1 form)) (>= (length form) 3)) - `(- (- ,(nth 2 form)) ,＠(nthcdr 3 form))) + ;; (- 0 ...) --> + ((eq 0 (nth 1 form)) + (case (length form) + ;; (- 0) --> 0 + (2 0) + ;; (- 0 x) --> (- x) + (3 `(- ,(nth 2 form))) + ;; (- 0 x y ...) --> (- (- x) y ...) + (t `(- (- ,(nth 2 form)) ,＠(nthcdr 3 form))))) (t (byte-optimize-predicate form))))) KY> I found the cause of this in the function `byte-optimize-minus'. KY> Here is a patch for it. KY> 2001-03-21 Katsumi Yamaoka <yamaoka(a)jpl.org&gt; KY> * byte-optimize.el (byte-optimize-minus): Fix. KY> --- byte-optimize.el~ Mon Jan 15 22:05:01 2001 KY> +++ byte-optimize.el Wed Mar 21 09:09:02 2001 KY> ＠＠ -729,8 +729,12 ＠＠ KY> (decf (nth 1 form) last) KY> (butlast form)) KY> + ;; (- 0 x) --> (- x) KY> + ((and (eq 0 (nth 1 form)) (= (length form) 3)) KY> + `(- ,(nth 2 form))) KY> + KY> ;; (- 0 x ...) --> (- (- x) ...) KY> - ((and (eq 0 (nth 1 form)) (>= (length form) 3)) KY> + ((and (eq 0 (nth 1 form)) (> (length form) 3)) KY> `(- (- ,(nth 2 form)) ,＠(nthcdr 3 form))) KY> (t (byte-optimize-predicate form))))) KY> -- KY> Katsumi Yamaoka <yamaoka(a)jpl.org&gt;