(modify-face-read-string): Return (nil) for "none".

(modify-face): Don't get error if (nil) is the argument.
(face-try-color-list): Don't check whether nil is a valid color.

diff --git a/lisp/faces.el b/lisp/faces.el
index 2a817eba10647fe1cbd7247ecfc344d194a55059..0fe0644c6dd1ace1f42ae82fa4ecd7ccf0e25619 100644 (file)
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -283,7 +283,7 @@ in that frame; otherwise change each frame."
            (format "Set face %s %s: " face name))
          alist)))
     (cond ((equal value "none")
-          nil)
+          '(nil))
          ((equal value "")
           default)
          (t value))))
@@ -297,6 +297,7 @@ in that frame; otherwise change each frame.
 FOREGROUND and BACKGROUND should be a colour name string (or list of strings to
 try) or nil.  STIPPLE should be a stipple pattern name string or nil.
 If nil, means do not change the display attribute corresponding to that arg.
+If (nil), that means clear out the attribute.
 
 BOLD-P, ITALIC-P, UNDERLINE-P, and INVERSE-P specify whether
 the face should be set bold, italic, underlined or in inverse-video,
@@ -345,9 +346,15 @@ If called interactively, prompts for a face name and face attributes."
      (message "Face %s: %s" face
       (mapconcat 'identity
        (delq nil
-       (list (and foreground (concat (downcase foreground) " foreground"))
-             (and background (concat (downcase background) " background"))
-             (and stipple (concat (downcase new-stipple-string) " stipple"))
+       (list (if (equal foreground '(nil))
+                 " no foreground"
+               (and foreground (concat (downcase foreground) " foreground")))
+             (if (equal background '(nil))
+                 " no background"
+               (and background (concat (downcase background) " background")))
+             (if (equal stipple '(nil))
+                 " no stipple"
+               (and stipple (concat (downcase new-stipple-string) " stipple")))
              (and bold-p "bold") (and italic-p "italic")
              (and inverse-p "inverse")
              (and underline-p "underline"))) ", "))
@@ -1581,7 +1588,7 @@ examine the brightness for you."
        (set-face-inverse-video-p face t frame)
       (let (done)
        (while (and colors (not done))
-         (if (or (memq (car colors) '(t underline))
+         (if (or (memq (car colors) '(t underline nil))
                  (face-color-supported-p frame (car colors)
                                          (eq function 'set-face-background)))
              (if (cdr colors)