Prefer '(evenp A)' to '(= 0 (% A 2))'evenp-oddp

* lisp/calc/calc-comb.el (math-prime-test):
* lisp/calc/calc-keypd.el (calc-keypad-press):
* lisp/calc/calc-math.el (math-sqrt):
(math-sqrt-raw):
* lisp/calc/calc-misc.el (math-iipow):
(math-iipow-show):
* lisp/calc/calc-stat.el (calcFunc-vmedian):
* lisp/calendar/cal-tex.el (cal-tex-cursor-filofax-2week):
(cal-tex-cursor-filofax-daily):
* lisp/elec-pair.el (electric-pair-post-self-insert-function):
* lisp/emacs-lisp/checkdoc.el (checkdoc-in-example-string-p):
* lisp/emacs-lisp/eieio.el (defclass):
* lisp/emacs-lisp/ert-x.el (ert-propertized-string):
* lisp/emacs-lisp/ert.el (ert--significant-plist-keys):
(ert--plist-difference-explanation):
* lisp/emacs-lisp/helper.el (Helper-help-scroller):
* lisp/emacs-lisp/pcase.el (pcase-setq):
* lisp/files-x.el (setq-connection-local):
* lisp/gnus/gnus-uu.el (gnus-uu-post-encoded):
* lisp/gnus/message.el (message-make-in-reply-to):
* lisp/gnus/nndiary.el (nndiary-last-occurrence):
(nndiary-next-occurrence):
* lisp/mail/rfc2047.el (rfc2047-decode-region):
* lisp/play/5x5.el (5x5-draw-grid):
* lisp/play/gametree.el (gametree-compute-reduced-score):
(gametree-insert-new-leaf):
(gametree-break-line-here):
* lisp/play/zone.el (zone-fret):
* lisp/vc/ediff-ptch.el (ediff-get-patch-buffer):
* lisp/yank-media.el (yank-media--utf-16-p): Prefer '(evenp A)' to
'(= 0 (% A 2))' and variations thereof.

23 files changed, 35 insertions, 35 deletions

diff --git a/lisp/calc/calc-comb.el b/lisp/calc/calc-comb.el
index 1ac3347b758..6e2fc08fece 100644
--- a/lisp/calc/calc-comb.el
+++ b/lisp/calc/calc-comb.el
@@ -826,8 +826,8 @@
                        '(t))))
                   ((not (equal n (car math-prime-test-cache)))
                    (cond ((if (consp n)
-                              (= (% (nth 1 n) 2) 0)
-                            (= (% n 2) 0))
+                              (evenp (nth 1 n))
+                            (evenp n))
                           '(nil 2))
                          ((if (consp n)
                               (= (% (nth 1 n) 5) 0)
diff --git a/lisp/calc/calc-keypd.el b/lisp/calc/calc-keypd.el
index 2a9c8e75214..ad2b1741181 100644
--- a/lisp/calc/calc-keypd.el
+++ b/lisp/calc/calc-keypd.el
@@ -411,7 +411,7 @@
     (if invhyp (calc-wrapper))  ; clear Inv and Hyp flags
     (unwind-protect
         (cond ((or (null cmd)
-                   (= (% row 2) 0))
+                   (evenp row))
                (beep))
               ((and (> (minibuffer-depth) 0))
                (cond (isstring
diff --git a/lisp/calc/calc-math.el b/lisp/calc/calc-math.el
index 53e5df30fad..49a64008e0a 100644
--- a/lisp/calc/calc-math.el
+++ b/lisp/calc/calc-math.el
@@ -402,7 +402,7 @@ If this can't be done, return NIL."
                                (math-div (math-float num-sqrt) den-sqrt))))))
    (and (eq (car-safe a) 'float)
         (if calc-symbolic-mode
-            (if (= (% (nth 2 a) 2) 0)
+            (if (evenp (nth 2 a))
                 (let ((res (cl-isqrt (nth 1 a))))
                   (if (= (* res res) (nth 1 a))
                       (math-make-float res (/ (nth 2 a) 2))
@@ -468,7 +468,7 @@ If this can't be done, return NIL."
      (t
       (if (null guess)
           (let ((ldiff (- (math-numdigs (nth 1 a)) 6)))
-            (or (= (% (+ (nth 2 a) ldiff) 2) 0) (setq ldiff (1+ ldiff)))
+            (or (evenp (+ (nth 2 a) ldiff)) (setq ldiff (1+ ldiff)))
             (setq guess (math-make-float (cl-isqrt
                                           (math-scale-int (nth 1 a) (- ldiff)))
                                          (/ (+ (nth 2 a) ldiff) 2)))))
diff --git a/lisp/calc/calc-misc.el b/lisp/calc/calc-misc.el
index 0772b76409a..564cbfc6537 100644
--- a/lisp/calc/calc-misc.el
+++ b/lisp/calc/calc-misc.el
@@ -898,7 +898,7 @@ loaded and the keystroke automatically re-typed."
 (defun math-iipow (a n)   ; [O O S]
   (cond ((= n 0) 1)
         ((= n 1) a)
-        ((= (% n 2) 0) (math-iipow (math-mul a a) (/ n 2)))
+        ((evenp n) (math-iipow (math-mul a a) (/ n 2)))
         (t (math-mul a (math-iipow (math-mul a a) (/ n 2))))))
 
 (defun math-iipow-show (a n)   ; [O O S]
@@ -906,7 +906,7 @@ loaded and the keystroke automatically re-typed."
   (let ((val (cond
               ((= n 0) 1)
               ((= n 1) a)
-              ((= (% n 2) 0) (math-iipow-show (math-mul a a) (/ n 2)))
+              ((evenp n) (math-iipow-show (math-mul a a) (/ n 2)))
               (t (math-mul a (math-iipow-show (math-mul a a) (/ n 2)))))))
     (math-working "pow" val)
     val))
diff --git a/lisp/calc/calc-stat.el b/lisp/calc/calc-stat.el
index 57f42645e34..cbf85c51ab4 100644
--- a/lisp/calc/calc-stat.el
+++ b/lisp/calc/calc-stat.el
@@ -390,7 +390,7 @@
               (math-reject-arg (car p) 'anglep))
           (setq p (cdr p)))
         (setq flat (sort flat 'math-lessp))
-        (if (= (% len 2) 0)
+        (if (evenp len)
             (math-div (math-add (nth (1- hlen) flat) (nth hlen flat)) 2)
           (nth hlen flat))))))
 
diff --git a/lisp/calendar/cal-tex.el b/lisp/calendar/cal-tex.el
index c0bb9760810..f5bdfb970cc 100644
--- a/lisp/calendar/cal-tex.el
+++ b/lisp/calendar/cal-tex.el
@@ -1295,7 +1295,7 @@ Optional EVENT indicates a buffer position to use instead of point."
     (cal-tex-b-document)
     (cal-tex-cmd "\\pagestyle" "empty")
     (dotimes (i n)
-      (if (zerop (mod i 2))
+      (if (evenp i)
           (insert "\\righthead")
         (insert "\\lefthead"))
       (cal-tex-arg
@@ -1318,7 +1318,7 @@ Optional EVENT indicates a buffer position to use instead of point."
                       (calendar-extract-year d))))))
       (insert "%\n")
       (dotimes (_jdummy 7)
-        (if (zerop (mod i 2))
+        (if (evenp i)
             (insert "\\rightday")
           (insert "\\leftday"))
         (cal-tex-arg (cal-tex-LaTeXify-string (calendar-day-name date)))
@@ -1388,7 +1388,7 @@ Optional EVENT indicates a buffer position to use instead of point."
     (cal-tex-cmd "\\pagestyle" "empty")
     (dotimes (i n)
       (dotimes (j 4)
-        (let ((even (zerop (% j 2))))
+        (let ((even (evenp j)))
           (insert (if even
                       "\\righthead"
                     "\\lefthead"))
diff --git a/lisp/elec-pair.el b/lisp/elec-pair.el
index 10c14e55eae..aa2577300fd 100644
--- a/lisp/elec-pair.el
+++ b/lisp/elec-pair.el
@@ -558,7 +558,7 @@ The decision is taken by order of preference:
         ;; Backslash-escaped: no pairing, no skipping.
         ((save-excursion
            (goto-char beg)
-           (not (zerop (% (skip-syntax-backward "\\") 2))))
+           (not (evenp (skip-syntax-backward "\\"))))
          (let ((current-prefix-arg (1- num)))
            (electric-pair-post-self-insert-function)))
         ;; Skip self.
diff --git a/lisp/emacs-lisp/checkdoc.el b/lisp/emacs-lisp/checkdoc.el
index dd3da9ae8c0..3541e3d0a57 100644
--- a/lisp/emacs-lisp/checkdoc.el
+++ b/lisp/emacs-lisp/checkdoc.el
@@ -2109,7 +2109,7 @@ The text checked is between START and LIMIT."
         (goto-char start)
         (while (and (< (point) p) (re-search-forward "\\\\\"" limit t))
           (setq c (1+ c)))
-        (and (< 0 c) (= (% c 2) 0))))))
+        (and (< 0 c) (evenp c))))))
 
 (defun checkdoc-in-abbreviation-p (begin)
   "Return non-nil if point is at an abbreviation.
diff --git a/lisp/emacs-lisp/eieio.el b/lisp/emacs-lisp/eieio.el
index 8665934ebfd..0f029813f80 100644
--- a/lisp/emacs-lisp/eieio.el
+++ b/lisp/emacs-lisp/eieio.el
@@ -115,7 +115,7 @@ and reference them using the function `class-option'."
   (cl-check-type superclasses list)
 
   (cond ((and (stringp (car options-and-doc))
-              (/= 1 (% (length options-and-doc) 2)))
+              (evenp (length options-and-doc)))
          (error "Too many arguments to `defclass'"))
         ((and (symbolp (car options-and-doc))
               (oddp (length options-and-doc)))
diff --git a/lisp/emacs-lisp/ert-x.el b/lisp/emacs-lisp/ert-x.el
index 147787d3d38..0dacec130a0 100644
--- a/lisp/emacs-lisp/ert-x.el
+++ b/lisp/emacs-lisp/ert-x.el
@@ -260,7 +260,7 @@ structure with the plists in ARGS."
                (string (let ((begin (point)))
                          (insert x)
                          (set-text-properties begin (point) current-plist)))
-               (list (unless (zerop (mod (length x) 2))
+               (list (unless (evenp (length x))
                        (error "Odd number of args in plist: %S" x))
                      (setq current-plist x))))
     (buffer-string)))
diff --git a/lisp/emacs-lisp/ert.el b/lisp/emacs-lisp/ert.el
index 5d1b9f2acbb..e8012326eb3 100644
--- a/lisp/emacs-lisp/ert.el
+++ b/lisp/emacs-lisp/ert.el
@@ -576,7 +576,7 @@ Return nil if they are."
 
 (defun ert--significant-plist-keys (plist)
   "Return the keys of PLIST that have non-null values, in order."
-  (cl-assert (zerop (mod (length plist) 2)) t)
+  (cl-assert (evenp (length plist)) t)
   (cl-loop for (key value . rest) on plist by #'cddr
            unless (or (null value) (memq key accu)) collect key into accu
            finally (cl-return accu)))
@@ -587,8 +587,8 @@ Return nil if they are."
 Returns nil if they are equivalent, i.e., have the same value for
 each key, where absent values are treated as nil.  The order of
 key/value pairs in each list does not matter."
-  (cl-assert (zerop (mod (length a) 2)) t)
-  (cl-assert (zerop (mod (length b) 2)) t)
+  (cl-assert (evenp (length a)) t)
+  (cl-assert (evenp (length b)) t)
   ;; Normalizing the plists would be another way to do this but it
   ;; requires a total ordering on all lisp objects (since any object
   ;; is valid as a text property key).  Perhaps defining such an
diff --git a/lisp/emacs-lisp/helper.el b/lisp/emacs-lisp/helper.el
index d8f758d2fe5..8a173219545 100644
--- a/lisp/emacs-lisp/helper.el
+++ b/lisp/emacs-lisp/helper.el
@@ -80,7 +80,7 @@
                  (recenter))
                 ((and (or (eq continue 'backspace)
                           (eq continue ?\177))
-                      (zerop (% state 2)))
+                      (evenp state))
                  (scroll-down))
                 (t (setq continue nil))))))))
 
diff --git a/lisp/emacs-lisp/pcase.el b/lisp/emacs-lisp/pcase.el
index a6a4751f49a..c68b8961ee3 100644
--- a/lisp/emacs-lisp/pcase.el
+++ b/lisp/emacs-lisp/pcase.el
@@ -370,7 +370,7 @@ undetected, binding variables to arbitrary values, such as nil.
   (cond
    (args
     (let ((arg-length (length args)))
-      (unless (= 0 (mod arg-length 2))
+      (unless (evenp arg-length)
         (signal 'wrong-number-of-arguments
                 (list 'pcase-setq (+ 2 arg-length)))))
     (let ((result))
diff --git a/lisp/files-x.el b/lisp/files-x.el
index 0e8b99c1e4f..3f57321eb53 100644
--- a/lisp/files-x.el
+++ b/lisp/files-x.el
@@ -914,7 +914,7 @@ earlier in the `setq-connection-local'.  The return value of the
 
 \(fn [VARIABLE VALUE]...)"
   (declare (debug setq))
-  (unless (zerop (mod (length pairs) 2))
+  (unless (evenp (length pairs))
     (error "PAIRS must have an even number of variable/value members"))
   (let ((set-expr nil)
         (profile-vars nil))
diff --git a/lisp/gnus/gnus-uu.el b/lisp/gnus/gnus-uu.el
index 4372fd58669..bf745be0f6e 100644
--- a/lisp/gnus/gnus-uu.el
+++ b/lisp/gnus/gnus-uu.el
@@ -2098,7 +2098,7 @@ If no file has been included, the user will be asked for a file."
                  (make-string minlen ?-)
                  file-name i parts
                  (make-string
-                  (if (= 0 (% whole-len 2)) (1- minlen) minlen) ?-)))
+                  (if (evenp whole-len) (1- minlen) minlen) ?-)))
 
         (goto-char (point-min))
         (when (re-search-forward "^Subject: " nil t)
diff --git a/lisp/gnus/message.el b/lisp/gnus/message.el
index dede5520d66..46c3550418f 100644
--- a/lisp/gnus/message.el
+++ b/lisp/gnus/message.el
@@ -6035,7 +6035,7 @@ In posting styles use `(\"Expires\" (make-expires-date 30))'."
                         (while (search-forward "\"" nil t)
                           (when (prog2
                                     (backward-char)
-                                    (zerop (% (skip-chars-backward "\\\\") 2))
+                                    (evenp (skip-chars-backward "\\\\"))
                                   (goto-char (match-beginning 0)))
                             (insert "\\"))
                           (forward-char))
diff --git a/lisp/gnus/nndiary.el b/lisp/gnus/nndiary.el
index de051745f92..7bc46fa88f8 100644
--- a/lisp/gnus/nndiary.el
+++ b/lisp/gnus/nndiary.el
@@ -1353,9 +1353,9 @@ all.  This may very well take some time.")
                        (max (cond ((= month 2)
                                    (if (date-leap-year-p year) 29 28))
                                   ((<= month 7)
-                                   (if (zerop (% month 2)) 30 31))
+                                   (if (evenp month) 30 31))
                                   (t
-                                   (if (zerop (% month 2)) 31 30))))
+                                   (if (evenp month) 31 30))))
                        (doms dom-list)
                        (dows dow-list)
                        day days)
@@ -1456,9 +1456,9 @@ all.  This may very well take some time.")
                        (max (cond ((= month 2)
                                    (if (date-leap-year-p year) 29 28))
                                   ((<= month 7)
-                                   (if (zerop (% month 2)) 30 31))
+                                   (if (evenp month) 30 31))
                                   (t
-                                   (if (zerop (% month 2)) 31 30))))
+                                   (if (evenp month) 31 30))))
                        (doms dom-list)
                        (dows dow-list)
                        day days)
diff --git a/lisp/mail/rfc2047.el b/lisp/mail/rfc2047.el
index 38b924851fc..13d1ac320b0 100644
--- a/lisp/mail/rfc2047.el
+++ b/lisp/mail/rfc2047.el
@@ -1076,7 +1076,7 @@ other than `\"' and `\\' in quoted strings."
                 (while (search-forward "\"" end t)
                   (when (prog2
                             (backward-char)
-                            (zerop (% (skip-chars-backward "\\\\") 2))
+                            (evenp (skip-chars-backward "\\\\"))
                           (goto-char (match-beginning 0)))
                     (insert "\\"))
                   (forward-char))
diff --git a/lisp/play/5x5.el b/lisp/play/5x5.el
index 3c5a3601927..e7638ef0f59 100644
--- a/lisp/play/5x5.el
+++ b/lisp/play/5x5.el
@@ -312,7 +312,7 @@ Quit current game           \\[5x5-quit-game]"
                   (forward-char  (+ 1 (/ (1+ 5x5-x-scale) 2)))
                   (dotimes (x 5x5-grid-size)
                     (when (5x5-cell solution-grid y x)
-                      (if (= 0 (mod 5x5-x-scale 2))
+                      (if (evenp 5x5-x-scale)
                           (progn
                             (insert "()")
                             (delete-region (point) (+ (point) 2))
diff --git a/lisp/play/gametree.el b/lisp/play/gametree.el
index c0d43944e67..8ffddfc7275 100644
--- a/lisp/play/gametree.el
+++ b/lisp/play/gametree.el
@@ -347,7 +347,7 @@ Subnodes which have been manually scored are honored."
         ;; be either a leaf child, or a subheading.
         (let ((running gametree-default-score)
               (minmax
-               (if (= 0 (mod (gametree-current-branch-ply) 2))
+               (if (evenp (gametree-current-branch-ply))
                    'max 'min)))
           (while (and (not (eobp))
                       (= 0 (gametree-current-branch-depth))) ;handle leaves
@@ -395,7 +395,7 @@ depth AT-DEPTH or smaller is found."
                              (gametree-current-branch-ply)))))
       (goto-char (1- (point)))
       (insert "\n")
-      (insert (format (if (= 0 (mod starting-plies 2))
+      (insert (format (if (evenp starting-plies)
                           gametree-full-ply-format
                         gametree-half-ply-format)
                       (/ starting-plies 2))))))
@@ -450,7 +450,7 @@ only work of Black's moves are explicitly numbered, for instance
                                    gametree-full-ply-regexp "\\|"
                                    gametree-half-ply-regexp "\\)")))
           (progn
-            (insert (format (if (= 0 (mod (gametree-looking-at-ply) 2))
+            (insert (format (if (evenp (gametree-looking-at-ply))
                                 gametree-full-ply-format
                               gametree-half-ply-format)
                             (/ (gametree-looking-at-ply) 2)))
diff --git a/lisp/play/zone.el b/lisp/play/zone.el
index b294dd6af67..39a33f1e2a0 100644
--- a/lisp/play/zone.el
+++ b/lisp/play/zone.el
@@ -454,7 +454,7 @@ run a specific program.  The program must be a member of
     (dotimes (i 20)
       (goto-char pos)
       (delete-char 1)
-      (insert (if (= 0 (% i 2)) hmm c-string))
+      (insert (if (evenp i) hmm c-string))
       (zone-park/sit-for wbeg (setq wait (* wait 0.8))))
     (delete-char -1) (insert c-string)))
 
diff --git a/lisp/vc/ediff-ptch.el b/lisp/vc/ediff-ptch.el
index 42b0d6850ef..1e66a016375 100644
--- a/lisp/vc/ediff-ptch.el
+++ b/lisp/vc/ediff-ptch.el
@@ -549,7 +549,7 @@ an optional argument, then use it."
 
     (cond ((ediff-buffer-live-p patch-buf))
           ;; even prefix arg: patch in buffer
-          ((and (integerp arg) (eq 0 (mod arg 2)))
+          ((and (integerp arg) (evenp arg))
            (setq patch-buf (ediff-prompt-for-patch-buffer)))
           ;; odd prefix arg: get patch from a file
           ((and (integerp arg) (oddp arg))
diff --git a/lisp/yank-media.el b/lisp/yank-media.el
index 600cc0ffaf5..bb62ba272d3 100644
--- a/lisp/yank-media.el
+++ b/lisp/yank-media.el
@@ -172,7 +172,7 @@ non-supported selection data types."
     data)))
 
 (defun yank-media--utf-16-p (data)
-  (and (zerop (mod (length data) 2))
+  (and (evenp (length data))
        (let ((stats (vector 0 0)))
          (dotimes (i (length data))
            (when (zerop (elt data i))