From: Dave Love <fx@gnu.org>
Date: Wed, 29 Nov 2000 19:12:51 +0000 (+0000)
Subject: plist-member
X-Git-Tag: emacs-pretest-21.0.93~370
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=4e5d744e9be8bf4d1c0b5217ebf4e51cd073db8f;p=emacs.git

plist-member
---

diff --git a/lispref/symbols.texi b/lispref/symbols.texi
index 290b57269ec..14f5c088606 100644
--- a/lispref/symbols.texi
+++ b/lispref/symbols.texi
@@ -521,7 +521,7 @@ The @code{put} function returns @var{value}.
 @node Other Plists
 @subsection Property Lists Outside Symbols
 
-  These two functions are useful for manipulating property lists
+  These functions are useful for manipulating property lists
 that are stored in places other than symbols:
 
 @defun plist-get plist property
@@ -558,3 +558,12 @@ in the place where you got @var{plist}.  For example,
   (setplist symbol
             (plist-put (symbol-plist symbol) prop value)))
 @end example
+
+@defun plist-member plist property
+@tindex plist-member
+This returns non-@code{nil} if @var{plist} contains the given
+@var{property}.  Unlike @code{plist-get}, this allows you to distinguish
+between a missing property and a property with the value @code{nil}.
+The value is actually the tail of @var{plist} whose @code{car} is
+@var{property}.
+@end defun