Re: ruler support in hexl mode

[Juanma Barranquero <lektu@terra.es>]

On 17 Mar 2004 12:59:31 +0900, Miles Bader <miles@lsi.nec.co.jp> wrote:

> Juanma Barranquero <jmbarranquero@wke.es> writes:
> > Time for a `make-obsolete-face' function? :)
> 
> It'd be nice...

Well, if there's really interest, I could commit the following patch:


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Index: faces.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/faces.el,v
retrieving revision 1.282
diff -u -2 -r1.282 faces.el
--- faces.el	27 Feb 2004 17:30:23 -0000	1.282
+++ faces.el	17 Mar 2004 10:16:35 -0000
@@ -1243,5 +1243,6 @@
 	  (if (not (facep f))
 	      (insert "   undefined face.\n")
-	    (let ((customize-label "customize this face"))
+	    (let ((customize-label "customize this face")
+                  (obsolete (get f 'byte-obsolete-face)))
 	      (princ (concat " (" customize-label ")\n"))
 	      (insert "Documentation: "
@@ -1249,4 +1250,12 @@
 			  "Not documented as a face.")
 		      "\n\n")
+              (when obsolete
+                (princ "This face is obsolete")
+                (if (cdr obsolete) (princ (format " since %s" (cdr obsolete))))
+                (princ ";") (terpri)
+                (princ (if (stringp (car obsolete)) (car obsolete)
+                         (format "use `%s' instead." (car obsolete))))
+                (terpri)
+                (terpri))
 	      (with-current-buffer standard-output
 		(save-excursion
Index: emacs-lisp/byte-run.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/emacs-lisp/byte-run.el,v
retrieving revision 1.3
diff -u -2 -r1.3 byte-run.el
--- emacs-lisp/byte-run.el	18 Mar 2004 00:17:17 -0000	1.3
+++ emacs-lisp/byte-run.el	17 Mar 2004 10:21:16 -0000
@@ -106,4 +106,21 @@
   var)
 
+(defun make-obsolete-face (face new &optional when)
+  "Make the byte-compiler warn that FACE is obsolete.
+The warning will say that NEW should be used instead.
+If NEW is a string, that is the `use instead' message.
+If provided, WHEN should be a string indicating when the face
+was first made obsolete, for example a date or a release number."
+  (interactive
+   (list
+    (let ((old (read-face-name "Make face obsolete")))
+      (if (equal old nil) (error ""))
+      old)
+    (let ((new (read-face-name "Obsoletion replacement")))
+      (if (equal new nil) (error "No replacement face"))
+      new)))
+  (put face 'byte-obsolete-face (cons new when))
+  face)
+
 (put 'dont-compile 'lisp-indent-hook 0)
 (defmacro dont-compile (&rest body)
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but the problem is, how to make the byte-compiler warn when using an
obsolete face? AFAICS, face names are just symbols, so other uses of the
symbol would trigger the warning too. For example, with this patch (just
a proof of concept, I know almost nothing about bytecomp.el):


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Index: bytecomp.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/emacs-lisp/bytecomp.el,v
retrieving revision 2.143
diff -u -2 -r2.143 bytecomp.el
--- bytecomp.el	12 Mar 2004 10:09:59 -0000	2.143
+++ bytecomp.el	18 Mar 2004 00:47:31 -0000
@@ -2788,5 +2788,14 @@
       (setq for-effect nil)
     (when (symbolp const)
-      (byte-compile-set-symbol-position const))
+      (byte-compile-set-symbol-position const)
+      (if (and (get const 'byte-obsolete-face)
+               (memq 'obsolete byte-compiler-warnings))
+          (let* ((ob (get const 'byte-obsolete-face))
+                 (when (cdr ob)))
+            (byte-compile-warn "%s is an obsolete face%s; %s" const
+                               (if when (concat " since " when) "")
+                               (if (stringp (car ob))
+                                   (car ob)
+                                 (format "use %s instead." (car ob)))))))
     (byte-compile-out 'byte-constant (byte-compile-get-constant const)))) 

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you can certainly do (make-obsolete-face 'modeline 'mode-line "21.5")
and get a warning in compilation, but then so does every other use of
'modeline, even if it's not used as a a face. Any easy way to solve this
or do it right?

                                                           /L/e/k/t/u