i18n: Add function ngettext for pluralization.

* lisp/international/mule-cmds.el (ngettext): New function.
https://lists.gnu.org/archive/html/emacs-devel/2019-03/msg00586.html

* lisp/replace.el (flush-lines, how-many, occur-1, occur-engine)
(perform-replace): Use ngettext.

* lisp/progmodes/grep.el (grep-exit-message): Use ngettext.
(grep-mode-font-lock-keywords): Match both singular and plural form
of "matches".

3 files changed, 49 insertions, 23 deletions

diff --git a/lisp/international/mule-cmds.el b/lisp/international/mule-cmds.el
index 5f87d899415..035932e395d 100644
--- a/lisp/international/mule-cmds.el
+++ b/lisp/international/mule-cmds.el
@@ -2798,6 +2798,20 @@ See also `locale-charset-language-names', `locale-language-names',
                       'a4)))))))
   nil)
 
+;;; i18n (internationalization)
+
+(defun ngettext (msgid msgid_plural n)
+  "Return the plural form of the translation of the string.
+This function is similar to the `gettext' function as it finds the message
+catalogs in the same way.  But it takes two extra arguments.  The MSGID
+parameter must contain the singular form of the string to be converted.
+It is also used as the key for the search in the catalog.
+The MSGID_PLURAL parameter is the plural form.  The parameter N is used
+to determine the plural form.  If no message catalog is found MSGID is
+returned if N is equal to 1, otherwise MSGID_PLURAL."
+  (if (= n 1) msgid msgid_plural))
+
+
 ;;; Character property
 
 (put 'char-code-property-table 'char-table-extra-slots 5)
diff --git a/lisp/progmodes/grep.el b/lisp/progmodes/grep.el
index a5427dd8b7e..c0f47159c95 100644
--- a/lisp/progmodes/grep.el
+++ b/lisp/progmodes/grep.el
@@ -459,7 +459,7 @@ abbreviated part can also be toggled with
      ;; remove match from grep-regexp-alist before fontifying
      ("^Grep[/a-zA-Z]* started.*"
       (0 '(face nil compilation-message nil help-echo nil mouse-face nil) t))
-     ("^Grep[/a-zA-Z]* finished with \\(?:\\(\\(?:[0-9]+ \\)?matches found\\)\\|\\(no matches found\\)\\).*"
+     ("^Grep[/a-zA-Z]* finished with \\(?:\\(\\(?:[0-9]+ \\)?match\\(?:es\\)? found\\)\\|\\(no matches found\\)\\).*"
       (0 '(face nil compilation-message nil help-echo nil mouse-face nil) t)
       (1 compilation-info-face nil t)
       (2 compilation-warning-face nil t))
@@ -552,7 +552,10 @@ Set up `compilation-exit-message-function' and run `grep-setup-hook'."
       ;; so the buffer is still unmodified if there is no output.
       (cond ((and (zerop code) (buffer-modified-p))
              (if (> grep-num-matches-found 0)
-                 (cons (format "finished with %d matches found\n" grep-num-matches-found)
+                 (cons (format (ngettext "finished with %d match found\n"
+                                         "finished with %d matches found\n"
+                                         grep-num-matches-found)
+                               grep-num-matches-found)
                        "matched")
                '("finished with matches found\n" . "matched")))
             ((not (buffer-modified-p))
diff --git a/lisp/replace.el b/lisp/replace.el
index 59ad1a375b8..318a9fb0253 100644
--- a/lisp/replace.el
+++ b/lisp/replace.el
@@ -983,7 +983,10 @@ also print the number."
                        (progn (forward-line 1) (point)))
         (setq count (1+ count))))
     (set-marker rend nil)
-    (when interactive (message "Deleted %d matching lines" count))
+    (when interactive (message (ngettext "Deleted %d matching line"
+                                         "Deleted %d matching lines"
+                                         count)
+                               count))
     count))
 
 (defun how-many (regexp &optional rstart rend interactive)
@@ -1032,9 +1035,10 @@ a previously found match."
         (if (= opoint (point))
             (forward-char 1)
           (setq count (1+ count))))
-      (when interactive (message "%d occurrence%s"
-                                 count
-                                 (if (= count 1) "" "s")))
+      (when interactive (message (ngettext "%d occurrence"
+                                           "%d occurrences"
+                                           count)
+                                 count))
       count)))
 
 
@@ -1617,11 +1621,12 @@ See also `multi-occur'."
                   (not (eq occur-excluded-properties t))))))
           (let* ((bufcount (length active-bufs))
                  (diff (- (length bufs) bufcount)))
-            (message "Searched %d buffer%s%s; %s match%s%s"
-                     bufcount (if (= bufcount 1) "" "s")
+            (message "Searched %d %s%s; %s %s%s"
+                     bufcount
+                     (ngettext "buffer" "buffers" bufcount)
                      (if (zerop diff) "" (format " (%d killed)" diff))
                      (if (zerop count) "no" (format "%d" count))
-                     (if (= count 1) "" "es")
+                     (ngettext "match" "matches" count)
                      ;; Don't display regexp if with remaining text
                      ;; it is longer than window-width.
                      (if (> (+ (length (or (get-text-property 0 'isearch-string regexp)
@@ -1856,14 +1861,15 @@ See also `multi-occur'."
                   (let ((beg (point))
                         end)
                     (insert (propertize
-                             (format "%d match%s%s%s in buffer: %s%s\n"
-                                     matches (if (= matches 1) "" "es")
+                             (format "%d %s%s%s in buffer: %s%s\n"
+                                     matches
+                                     (ngettext "match" "matches" matches)
                                      ;; Don't display the same number of lines
                                      ;; and matches in case of 1 match per line.
                                      (if (= lines matches)
-                                         "" (format " in %d line%s"
+                                         "" (format " in %d %s"
                                                     lines
-                                                    (if (= lines 1) "" "s")))
+                                                    (ngettext "line" "lines" lines)))
                                      ;; Don't display regexp for multi-buffer.
                                      (if (> (length buffers) 1)
                                          "" (occur-regexp-descr regexp))
@@ -1889,13 +1895,15 @@ See also `multi-occur'."
         (goto-char (point-min))
         (let ((beg (point))
               end)
-          (insert (format "%d match%s%s total%s:\n"
-                          global-matches (if (= global-matches 1) "" "es")
+          (insert (format "%d %s%s total%s:\n"
+                          global-matches
+                          (ngettext "match" "matches" global-matches)
                           ;; Don't display the same number of lines
                           ;; and matches in case of 1 match per line.
                           (if (= global-lines global-matches)
-                              "" (format " in %d line%s"
-                                         global-lines (if (= global-lines 1) "" "s")))
+                              "" (format " in %d %s"
+                                         global-lines
+                                         (ngettext "line" "lines" global-lines)))
                           (occur-regexp-descr regexp)))
           (setq end (point))
           (when title-face
@@ -2730,10 +2738,10 @@ characters."
                                            (1+ num-replacements))))))
                              (when (and (eq def 'undo-all)
                                         (null (zerop num-replacements)))
-                               (message "Undid %d %s" num-replacements
-                                        (if (= num-replacements 1)
-                                            "replacement"
-                                          "replacements"))
+                               (message (ngettext "Undid %d replacement"
+                                                  "Undid %d replacements"
+                                                  num-replacements)
+                                        num-replacements)
                                (ding 'no-terminate)
                                (sit-for 1)))
                            (setq replaced nil last-was-undo t last-was-act-and-show nil)))
@@ -2859,9 +2867,10 @@ characters."
                       last-was-act-and-show     nil))))))
       (replace-dehighlight))
     (or unread-command-events
-        (message "Replaced %d occurrence%s%s"
+        (message (ngettext "Replaced %d occurrence%s"
+                           "Replaced %d occurrences%s"
+                           replace-count)
                  replace-count
-                 (if (= replace-count 1) "" "s")
                  (if (> (+ skip-read-only-count
                            skip-filtered-count
                            skip-invisible-count)