plist-member

diff --git a/lispref/symbols.texi b/lispref/symbols.texi
index 290b57269ec4d12d8a13c27c17e739a3cd70b55d..14f5c0886066d18e24c1ea4c08622147d6d60b49 100644 (file)
--- 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