Add a new face for non-breaking hyphen characters

* doc/emacs/display.texi (Standard Faces): Mention nobreak-hyphen.
(Text Display): Ditto.

* lisp/faces.el (nobreak-hyphen): New face (bug#12048).

* src/xdisp.c (get_next_display_element): Use it instead of
the escape-glyph face.

* src/xdisp.c (syms_of_xdisp): New symbil Qnobreak_hyphen.

doc/emacs/display.texi

@@ -657,6 +657,9 @@ The face for displaying control characters and escape sequences
 @item nobreak-space
 The face for displaying no-break space characters (@pxref{Text
 Display}).
+@item nobreak-hyphen
+The face for displaying no-break hyphen characters (@pxref{Text
+Display}).
 @end table
 
   The following faces control the appearance of parts of the Emacs
@@ -1481,7 +1484,7 @@ characters.  To deal with this problem, Emacs displays such characters
 specially: it displays @code{U+00A0} (no-break space) with the
 @code{nobreak-space} face, and it displays @code{U+00AD} (soft
 hyphen), @code{U+2010} (hyphen), and @code{U+2011} (non-breaking
-hyphen) with the @code{escape-glyph} face.  To disable this, change
+hyphen) with the @code{nobreak-hyphen} face.  To disable this, change
 the variable @code{nobreak-char-display} to @code{nil}.  If you give
 this variable a non-@code{nil} and non-@code{t} value, Emacs instead
 displays such characters as a highlighted backslash followed by a

etc/NEWS

@@ -56,6 +56,9 @@ affected by this, as SGI stopped supporting IRIX in December 2013.
 
 * Changes in Emacs 25.2
 
+** Non-breaking hypens are now displayed with the `nobreak-hyphen'
+face instead of the `escape-glyph' face.
+
 ---
 ** `C-x h' (`mark-whole-buffer') will now avoid marking the prompt
 part of minibuffers.

lisp/faces.el

@@ -2428,13 +2428,21 @@ If you set `term-file-prefix' to nil, this function does nothing."
   :version "22.1")
 
 (defface nobreak-space
-  '((((class color) (min-colors 88)) :inherit escape-glyph :underline t)
-    (((class color) (min-colors 8)) :background "magenta")
-    (t :inverse-video t))
+  '((((background dark)) :foreground "cyan")
+    (((type pc)) :foreground "magenta")
+    (t :foreground "brown"))
   "Face for displaying nobreak space."
   :group 'basic-faces
   :version "22.1")
 
+(defface nobreak-hyphen
+  '((((background dark)) :foreground "cyan")
+    (((type pc)) :foreground "magenta")
+    (t :foreground "brown"))
+  "Face for displaying nobreak hyphens."
+  :group 'basic-faces
+  :version "25.2")
+
 (defgroup mode-line-faces nil
   "Faces used in the mode line."
   :group 'mode-line

src/xdisp.c

@@ -7080,6 +7080,19 @@ get_next_display_element (struct it *it)
 		  goto display_control;
 		}
 
+	      /* Handle non-ascii hyphens in the mode where it only
+		 gets highlighting.  */
+
+	      if (nonascii_hyphen_p && EQ (Vnobreak_char_display, Qt))
+		{
+		  /* Merge `nobreak-space' into the current face.  */
+		  face_id = merge_faces (it->f, Qnobreak_hyphen, 0,
+					 it->face_id);
+		  XSETINT (it->ctl_chars[0], '-');
+		  ctl_len = 1;
+		  goto display_control;
+		}
+
 	      /* Handle sequences that start with the "escape glyph".  */
 
 	      /* the default escape glyph is \.  */
@@ -7096,15 +7109,6 @@ get_next_display_element (struct it *it)
 			 ? merge_faces (it->f, Qt, lface_id, it->face_id)
 			 : merge_escape_glyph_face (it));
 
-	      /* Draw non-ASCII hyphen with just highlighting: */
-
-	      if (nonascii_hyphen_p && EQ (Vnobreak_char_display, Qt))
-		{
-		  XSETINT (it->ctl_chars[0], '-');
-		  ctl_len = 1;
-		  goto display_control;
-		}
-
 	      /* Draw non-ASCII space/hyphen with escape glyph: */
 
 	      if (nonascii_space_p || nonascii_hyphen_p)
@@ -31198,8 +31202,10 @@ They are still logged to the *Messages* buffer.  */);
   /* Name and number of the face used to highlight escape glyphs.  */
   DEFSYM (Qescape_glyph, "escape-glyph");
 
-  /* Name and number of the face used to highlight non-breaking spaces.  */
+  /* Name and number of the face used to highlight non-breaking
+     spaces/hyphens.  */
   DEFSYM (Qnobreak_space, "nobreak-space");
+  DEFSYM (Qnobreak_hyphen, "nobreak-hyphen");
 
   /* The symbol 'image' which is the car of the lists used to represent
      images in Lisp.  Also a tool bar style.  */
@@ -31311,7 +31317,7 @@ The face used for trailing whitespace is `trailing-whitespace'.  */);
     doc: /* Control highlighting of non-ASCII space and hyphen chars.
 If the value is t, Emacs highlights non-ASCII chars which have the
 same appearance as an ASCII space or hyphen, using the `nobreak-space'
-or `escape-glyph' face respectively.
+or `nobreak-hyphen' face respectively.
 
 U+00A0 (no-break space), U+00AD (soft hyphen), U+2010 (hyphen), and
 U+2011 (non-breaking hyphen) are affected.