From: Glenn Morris <rgm@gnu.org>
Date: Sat, 1 Mar 2008 20:30:51 +0000 (+0000)
Subject: More info on how to replace make-variable-frame-local.
X-Git-Tag: emacs-pretest-22.1.92~28
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=59cd993bbda67978f1c25e205b9c429cd30e267f;p=emacs.git

More info on how to replace make-variable-frame-local.
---

diff --git a/etc/NEWS b/etc/NEWS
index 53b6d2d2732..5971c479658 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -135,7 +135,15 @@ because they clash with commands provided by dirtrack.el.  Use
 * Lisp Changes in Emacs 22.2.
 
 ** Frame-local variables are deprecated and are slated for removal.
-Use frame parameters instead.
+They can easily be emulated.  Rather than calling `make-variable-frame-local'
+and accessing the variable value directly, explicitly check for a
+frame-parameter, and if there is one, use its value in preference to
+that of the variable. Eg:
+(let ((fp (assoc 'var (frame-parameters))))
+  ;; Use frame-parameter, even if nil.
+  (if fp (cdr fp)
+     ;; Else use normal variable value.
+     var))
 
 ** The function invisible-p returns non-nil if the character
 after a specified position is invisible.