(describe-text-category): Use *Help*. Don't kill-buffer.

(describe-text-properties, describe-char):
Delay self-inspection test.  Use *Help*.
Use syntax-after.  Use `pos' rather than (point).
Distinguish the before/after part of a composition.

diff --git a/lisp/descr-text.el b/lisp/descr-text.el
index 5ef3a2990d87bbd7217a3a3e347574090302c063..aacec848756947cd315a6850536f64b957ca80e5 100644 (file)
--- a/lisp/descr-text.el
+++ b/lisp/descr-text.el
@@ -136,11 +136,9 @@ The `category' property is made into a widget button that call
 (defun describe-text-category (category)
   "Describe a text property category."
   (interactive "S")
-  (when (get-buffer "*Text Category*")
-    (kill-buffer "*Text Category*"))
   (save-excursion
-    (with-output-to-temp-buffer "*Text Category*"
-      (set-buffer "*Text Category*")
+    (with-output-to-temp-buffer "*Help*"
+      (set-buffer standard-output)
       (widget-insert "Category " (format "%S" category) ":\n\n")
       (describe-property-list (symbol-plist category))
       (describe-text-mode)
@@ -154,8 +152,6 @@ If optional second argument OUTPUT-BUFFER is non-nil,
 insert the output into that buffer, and don't initialize or clear it
 otherwise."
   (interactive "d")
-  (when (eq (current-buffer) (get-buffer "*Text Description*"))
-    (error "Can't do self inspection"))
   (if (>= pos (point-max))
       (error "No character follows specified position"))
   (if output-buffer
@@ -163,9 +159,11 @@ otherwise."
     (if (not (or (text-properties-at pos) (overlays-at pos)))
        (message "This is plain text.")
       (let ((buffer (current-buffer)))
+       (when (eq buffer (get-buffer "*Help*"))
+         (error "Can't do self inspection"))
        (save-excursion
-         (with-output-to-temp-buffer "*Text Description*"
-           (set-buffer "*Text Description*")
+         (with-output-to-temp-buffer "*Help*"
+           (set-buffer standard-output)
            (setq output-buffer (current-buffer))
            (widget-insert "Text content at position " (format "%d" pos) ":\n\n")
            (with-current-buffer buffer
@@ -226,14 +224,12 @@ syntax, category, how the character is encoded in a file,
 character composition information (if relevant),
 as well as widgets, buttons, overlays, and text properties."
   (interactive "d")
-  (when (eq (current-buffer) (get-buffer "*Text Description*"))
-    (error "Can't do self inspection"))
   (if (>= pos (point-max))
       (error "No character follows specified position"))
   (let* ((char (char-after pos))
         (charset (char-charset char))
         (buffer (current-buffer))
-        (composition (find-composition (point) nil nil t))
+        (composition (find-composition pos nil nil t))
         (composed (if composition (buffer-substring (car composition)
                                                     (nth 1 composition))))
         (multibyte-p enable-multibyte-characters)
@@ -261,11 +257,9 @@ as well as widgets, buttons, overlays, and text properties."
                      (format "%d" (nth 1 split))
                    (format "%d %d" (nth 1 split) (nth 2 split)))))
              ("syntax"
-              ,(let ((syntax (get-char-property (point) 'syntax-table)))
+              ,(let ((syntax (syntax-after pos)))
                  (with-temp-buffer
-                   (internal-describe-syntax-value
-                    (if (consp syntax) syntax
-                      (aref (or syntax (syntax-table)) char)))
+                   (internal-describe-syntax-value syntax)
                    (buffer-string))))
              ("category"
               ,@(let ((category-set (char-category-set char)))
@@ -293,16 +287,15 @@ as well as widgets, buttons, overlays, and text properties."
                     (list "not encodable by coding system"
                           (symbol-name coding)))))
              ,@(if (or (memq 'mule-utf-8
-                         (find-coding-systems-region (point) (1+ (point))))
-                       (get-char-property (point) 'untranslated-utf-8))
-                   (let ((uc (or (get-char-property (point)
-                                                    'untranslated-utf-8)
-                                 (encode-char (char-after) 'ucs))))
+                         (find-coding-systems-region pos (1+ pos)))
+                       (get-char-property pos 'untranslated-utf-8))
+                   (let ((uc (or (get-char-property pos 'untranslated-utf-8)
+                                 (encode-char char 'ucs))))
                      (if uc
                          (list (list "Unicode"
                                      (format "%04X" uc))))))
              ,(if (display-graphic-p (selected-frame))
-                  (list "font" (or (internal-char-font (point))
+                  (list "font" (or (internal-char-font pos)
                                    "-- none --"))
                 (list "terminal code"
                       (let* ((coding (terminal-coding-system))
@@ -312,11 +305,10 @@ as well as widgets, buttons, overlays, and text properties."
                           "not encodable")))))))
     (setq max-width (apply #'max (mapcar #'(lambda (x) (length (car x)))
                                         item-list)))
-    (when (get-buffer "*Help*")
-      (kill-buffer "*Help*"))
+    (when (eq (current-buffer) (get-buffer "*Help*"))
+      (error "Can't do self inspection"))
     (with-output-to-temp-buffer "*Help*"
-      (save-excursion
-       (set-buffer standard-output)
+      (with-current-buffer standard-output
        (set-buffer-multibyte multibyte-p)
        (let ((formatter (format "%%%ds:" max-width)))
          (dolist (elt item-list)
@@ -331,11 +323,20 @@ as well as widgets, buttons, overlays, and text properties."
              (insert " " clm))
            (insert "\n")))
        (when composition
-         (insert "\nComposed with the following character(s) "
-                 (mapconcat (lambda (x) (format "`%c'" x))
-                            (substring composed 1)
-                            ", ")
-                 " to form `" composed "'")
+         (insert "\nComposed with the "
+                 (cond
+                  ((eq pos (car composition)) "following ")
+                  ((eq (1+ pos) (cadr composition)) "preceding ")
+                  (t ""))
+                 "character(s) `"
+                 (cond
+                  ((eq pos (car composition)) (substring composed 1))
+                  ((eq (1+ pos) (cadr composition)) (substring composed 0 -1))
+                  (t (concat (substring composed 0 (- pos (car composition)))
+                             "' and `"
+                             (substring composed (- (1+ pos) (car composition))))))
+                   
+                 "' to form `" composed "'")
          (if (nth 3 composition)
              (insert ".\n")
            (insert "\nby the rule ("