(describe-face): Output a definition link button.

diff --git a/lisp/faces.el b/lisp/faces.el
index b018d5a57a7a1de2a68c2b8cecc5640f6508780f..6b3811a3d26845f06570c491ce5af08d01c5de22 100644 (file)
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -1257,17 +1257,32 @@ If FRAME is omitted or nil, use the selected frame."
          (insert "Face: " (symbol-name f))
          (if (not (facep f))
              (insert "   undefined face.\n")
-           (let ((customize-label "customize this face"))
+           (let ((customize-label "customize this face")
+                 file-name)
              (princ (concat " (" customize-label ")\n"))
              (insert "Documentation: "
                      (or (face-documentation f)
                          "Not documented as a face.")
-                     "\n\n")
+                     "\n")
              (with-current-buffer standard-output
                (save-excursion
                  (re-search-backward
                   (concat "\\(" customize-label "\\)") nil t)
                  (help-xref-button 1 'help-customize-face f)))
+             ;; The next 4 sexps are copied from describe-function-1
+             ;; and simplified.
+             (setq file-name (symbol-file f 'defface))
+             (when file-name
+               (princ "Defined in `")
+               (princ file-name)
+               (princ "'")
+               ;; Make a hyperlink to the library.
+               (save-excursion
+                 (re-search-backward "`\\([^`']+\\)'" nil t)
+                 (help-xref-button 1 'help-face-def f file-name))
+               (princ ".")
+               (terpri)
+               (terpri))
              (dolist (a attrs)
                (let ((attr (face-attribute f (car a) frame)))
                  (insert (make-string (- max-width (length (cdr a))) ?\ )
@@ -2047,7 +2062,7 @@ Note: Other faces cannot inherit from the cursor face."
     (t :inverse-video t))
   "Basic face for highlighting trailing whitespace."
   :version "21.1"
-  :group 'font-lock                    ; like `show-trailing-whitespace'
+  :group 'whitespace           ; like `show-trailing-whitespace'
   :group 'basic-faces)
 
 (defface escape-glyph '((((background dark)) :foreground "cyan")