(describe-categories): Display the terse legend at the head.

diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index 612b90ff62b3d27742d177315c376f044d5e3d8d..d08c184e1f57a7d135f89e726edda4eb3888e84a 100644 (file)
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -780,20 +780,48 @@ BUFFER should be a buffer or a buffer name."
   (setq buffer (or buffer (current-buffer)))
   (help-setup-xref (list #'describe-categories buffer) (interactive-p))
   (with-help-window (help-buffer)
-    (let ((table (with-current-buffer buffer (category-table))))
+    (let* ((table (with-current-buffer buffer (category-table)))
+          (docs (char-table-extra-slot table 0)))
+      (if (or (not (vectorp docs)) (/= (length docs) 95))
+         (error "Invalid first extra slot in this category table\n"))
       (with-current-buffer standard-output
+       (insert "Legend of category mnemonics (see the tail for the longer description)\n")
+       (let ((pos (point)) (items 0) lines n)
+         (dotimes (i 95)
+           (if (aref docs i) (setq items (1+ items))))
+         (setq lines (1+ (/ (1- items) 4)))
+         (setq n 0)
+         (dotimes (i 95)
+           (let ((elt (aref docs i)))
+             (when elt
+               (string-match ".*" elt)
+               (setq elt (match-string 0 elt))
+               (if (>= (length elt) 17)
+                   (setq elt (concat (substring elt 0 14) "...")))
+               (if (< (point) (point-max))
+                   (move-to-column (* 20 (/ n lines)) t))
+               (insert (+ i ?\s) ?: elt)
+               (if (< (point) (point-max))
+                   (forward-line 1)
+                 (insert "\n"))
+               (setq n (1+ n))
+               (if (= (% n lines) 0)
+                   (goto-char pos))))))
+       (goto-char (point-max))
+       (insert "\n"
+               "character(s)\tcategory mnemonics\n"
+               "------------\t------------------")
        (describe-vector table 'help-describe-category-set)
-       (let ((docs (char-table-extra-slot table 0)))
-         (if (or (not (vectorp docs)) (/= (length docs) 95))
-             (insert "Invalid first extra slot in this char table\n")
-           (insert "Meanings of mnemonic characters are:\n")
-           (dotimes (i 95)
-             (let ((elt (aref docs i)))
-               (when elt
-                 (insert (+ i ?\s) ": " elt "\n"))))
-           (while (setq table (char-table-parent table))
-             (insert "\nThe parent category table is:")
-             (describe-vector table 'help-describe-category-set))))))))
+       (insert "Legend of category mnemonics:\n")
+       (dotimes (i 95)
+         (let ((elt (aref docs i)))
+           (when elt
+             (if (string-match "\n" elt)
+                 (setq elt (substring elt (match-end 0))))
+             (insert (+ i ?\s) ": " elt "\n"))))
+       (while (setq table (char-table-parent table))
+         (insert "\nThe parent category table is:")
+         (describe-vector table 'help-describe-category-set))))))
 
 (provide 'help-fns)