Lisp manual improvements for plists and symbol plists.

* doc/lispref/commands.texi (Using Interactive): Fix index entry.

* doc/lispref/customize.texi (Variable Definitions):
* doc/lispref/display.texi (Defining Faces):
* doc/lispref/sequences.texi (Char-Tables): Fix xref.

* doc/lispref/lists.texi (Property Lists): Move here from symbols.texi.
(Plist Access): Rename from Other Plists.

* doc/lispref/symbols.texi (Symbol Properties): New node.
(Symbol Plists): Make it a subsection under Symbol Properties.
(Standard Properties): New node.

9 files changed, 314 insertions, 175 deletions

diff --git a/doc/lispref/ChangeLog b/doc/lispref/ChangeLog
index b55ded918bb..22f20c7112c 100644
--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
@@ -1,7 +1,20 @@
 2012-12-02  Chong Yidong  <cyd@gnu.org>
 
+	* symbols.texi (Symbol Properties): New node.
+	(Symbol Plists): Make it a subsection under Symbol Properties.
+	(Standard Properties): New node.
+
+	* lists.texi (Property Lists): Move here from symbols.texi.
+	(Plist Access): Rename from Other Plists.
+
+	* customize.texi (Variable Definitions):
+	* display.texi (Defining Faces):
+	* sequences.texi (Char-Tables): Fix xref.
+
 	* keymaps.texi (Key Sequences): kbd is now a function.
 
+	* commands.texi (Using Interactive): Fix index entry.
+
 2012-11-23  Martin Rudalics  <rudalics@gmx.at>
 
 	* windows.texi (Basic Windows): Fix typo.
diff --git a/doc/lispref/commands.texi b/doc/lispref/commands.texi
index c42e4b3b6dc..8806c933bf3 100644
--- a/doc/lispref/commands.texi
+++ b/doc/lispref/commands.texi
@@ -141,10 +141,10 @@ A command may be called from Lisp programs like any other function, but
 then the caller supplies the arguments and @var{arg-descriptor} has no
 effect.
 
-@cindex @code{interactive-form}, function property
+@cindex @code{interactive-form}, symbol property
 The @code{interactive} form must be located at top-level in the
 function body, or in the function symbol's @code{interactive-form}
-property (@pxref{Symbol Plists}).  It has its effect because the
+property (@pxref{Symbol Properties}).  It has its effect because the
 command loop looks for it before calling the function
 (@pxref{Interactive Call}).  Once the function is called, all its body
 forms are executed; at this time, if the @code{interactive} form
diff --git a/doc/lispref/customize.texi b/doc/lispref/customize.texi
index c9d22851ed2..d85361499ba 100644
--- a/doc/lispref/customize.texi
+++ b/doc/lispref/customize.texi
@@ -472,8 +472,8 @@ Internally, @code{defcustom} uses the symbol property
 @code{saved-value} to record the value saved by the user with the
 customization buffer, and @code{customized-value} to record the value
 set by the user with the customization buffer, but not saved.
-@xref{Property Lists}.  These properties are lists, the car of which
-is an expression that evaluates to the value.
+@xref{Symbol Properties}.  These properties are lists, the car of
+which is an expression that evaluates to the value.
 
 @defun custom-reevaluate-setting symbol
 This function re-evaluates the standard value of @var{symbol}, which
diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 475a9550f99..6799d3130b6 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -2287,7 +2287,7 @@ terminal must match one of the @var{value}s specified for it in
 @end example
 
   Internally, Emacs stores the face's default specification in its
-@code{face-defface-spec} symbol property (@pxref{Property Lists}).
+@code{face-defface-spec} symbol property (@pxref{Symbol Properties}).
 The @code{saved-face} property stores the face specification saved by
 the user, using the customization buffer; the @code{customized-face}
 property stores the face specification customized for the current
diff --git a/doc/lispref/elisp.texi b/doc/lispref/elisp.texi
index cb00b5e9889..b2b73b380b4 100644
--- a/doc/lispref/elisp.texi
+++ b/doc/lispref/elisp.texi
@@ -378,6 +378,7 @@ Lists
 * Modifying Lists::         Storing new pieces into an existing list.
 * Sets And Lists::          A list can represent a finite mathematical set.
 * Association Lists::       A list can represent a finite relation or mapping.
+* Property Lists::          A list of paired elements.
 
 Modifying Existing List Structure
 
@@ -386,6 +387,12 @@ Modifying Existing List Structure
                               This can be used to remove or add elements.
 * Rearrangement::           Reordering the elements in a list; combining lists.
 
+Property Lists
+
+* Plists and Alists::       Comparison of the advantages of property
+                              lists and association lists.
+* Plist Access::            Accessing property lists stored elsewhere.
+
 Sequences, Arrays, and Vectors
 
 * Sequence Functions::      Functions that accept any kind of sequence.
@@ -410,15 +417,13 @@ Symbols
                               and property lists.
 * Definitions::             A definition says how a symbol will be used.
 * Creating Symbols::        How symbols are kept unique.
-* Property Lists::          Each symbol has a property list
+* Symbol Properties::       Each symbol has a property list
                               for recording miscellaneous information.
 
-Property Lists
+Symbol Properties
 
-* Plists and Alists::       Comparison of the advantages of property
-                              lists and association lists.
-* Symbol Plists::           Functions to access symbols' property lists.
-* Other Plists::            Accessing property lists stored elsewhere.
+* Symbol Plists::           Accessing symbol properties.
+* Standard Properties::     Standard meanings of symbol properties.
 
 Evaluation
 
diff --git a/doc/lispref/lists.texi b/doc/lispref/lists.texi
index 40e8d08f72c..1a3d85b9b35 100644
--- a/doc/lispref/lists.texi
+++ b/doc/lispref/lists.texi
@@ -22,6 +22,7 @@ the whole list.
 * Modifying Lists::     Storing new pieces into an existing list.
 * Sets And Lists::      A list can represent a finite mathematical set.
 * Association Lists::   A list can represent a finite relation or mapping.
+* Property Lists::      A list of paired elements.
 @end menu
 
 @node Cons Cells
@@ -1821,3 +1822,142 @@ often modifies the original list structure of @var{alist}.
 compares the @sc{cdr} of each @var{alist} association instead of the
 @sc{car}.
 @end defun
+
+@node Property Lists
+@section Property Lists
+@cindex property list
+@cindex plist
+
+  A @dfn{property list} (@dfn{plist} for short) is a list of paired
+elements.  Each of the pairs associates a property name (usually a
+symbol) with a property or value.  Here is an example of a property
+list:
+
+@example
+(pine cones numbers (1 2 3) color "blue")
+@end example
+
+@noindent
+This property list associates @code{pine} with @code{cones},
+@code{numbers} with @code{(1 2 3)}, and @code{color} with
+@code{"blue"}.  The property names and values can be any Lisp objects,
+but the names are usually symbols (as they are in this example).
+
+  Property lists are used in several contexts.  For instance, the
+function @code{put-text-property} takes an argument which is a
+property list, specifying text properties and associated values which
+are to be applied to text in a string or buffer.  @xref{Text
+Properties}.
+
+  Another prominent use of property lists is for storing symbol
+properties.  Every symbol possesses a list of properties, used to
+record miscellaneous information about the symbol; these properties
+are stored in the form of a property list.  @xref{Symbol Properties}.
+
+@menu
+* Plists and Alists::           Comparison of the advantages of property
+                                  lists and association lists.
+* Plist Access::                Accessing property lists stored elsewhere.
+@end menu
+
+@node Plists and Alists
+@subsection Property Lists and Association Lists
+@cindex plist vs. alist
+@cindex alist vs. plist
+
+@cindex property lists vs association lists
+  Association lists (@pxref{Association Lists}) are very similar to
+property lists.  In contrast to association lists, the order of the
+pairs in the property list is not significant, since the property
+names must be distinct.
+
+  Property lists are better than association lists for attaching
+information to various Lisp function names or variables.  If your
+program keeps all such information in one association list, it will
+typically need to search that entire list each time it checks for an
+association for a particular Lisp function name or variable, which
+could be slow.  By contrast, if you keep the same information in the
+property lists of the function names or variables themselves, each
+search will scan only the length of one property list, which is
+usually short.  This is why the documentation for a variable is
+recorded in a property named @code{variable-documentation}.  The byte
+compiler likewise uses properties to record those functions needing
+special treatment.
+
+  However, association lists have their own advantages.  Depending on
+your application, it may be faster to add an association to the front of
+an association list than to update a property.  All properties for a
+symbol are stored in the same property list, so there is a possibility
+of a conflict between different uses of a property name.  (For this
+reason, it is a good idea to choose property names that are probably
+unique, such as by beginning the property name with the program's usual
+name-prefix for variables and functions.)  An association list may be
+used like a stack where associations are pushed on the front of the list
+and later discarded; this is not possible with a property list.
+
+@node Plist Access
+@subsection Property Lists Outside Symbols
+
+  The following functions can be used to manipulate property lists.
+They all compare property names using @code{eq}.
+
+@defun plist-get plist property
+This returns the value of the @var{property} property stored in the
+property list @var{plist}.  It accepts a malformed @var{plist}
+argument.  If @var{property} is not found in the @var{plist}, it
+returns @code{nil}.  For example,
+
+@example
+(plist-get '(foo 4) 'foo)
+     @result{} 4
+(plist-get '(foo 4 bad) 'foo)
+     @result{} 4
+(plist-get '(foo 4 bad) 'bad)
+     @result{} nil
+(plist-get '(foo 4 bad) 'bar)
+     @result{} nil
+@end example
+@end defun
+
+@defun plist-put plist property value
+This stores @var{value} as the value of the @var{property} property in
+the property list @var{plist}.  It may modify @var{plist} destructively,
+or it may construct a new list structure without altering the old.  The
+function returns the modified property list, so you can store that back
+in the place where you got @var{plist}.  For example,
+
+@example
+(setq my-plist '(bar t foo 4))
+     @result{} (bar t foo 4)
+(setq my-plist (plist-put my-plist 'foo 69))
+     @result{} (bar t foo 69)
+(setq my-plist (plist-put my-plist 'quux '(a)))
+     @result{} (bar t foo 69 quux (a))
+@end example
+@end defun
+
+  You could define @code{put} in terms of @code{plist-put} as follows:
+
+@example
+(defun put (symbol prop value)
+  (setplist symbol
+            (plist-put (symbol-plist symbol) prop value)))
+@end example
+
+@defun lax-plist-get plist property
+Like @code{plist-get} except that it compares properties
+using @code{equal} instead of @code{eq}.
+@end defun
+
+@defun lax-plist-put plist property value
+Like @code{plist-put} except that it compares properties
+using @code{equal} instead of @code{eq}.
+@end defun
+
+@defun plist-member plist property
+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
diff --git a/doc/lispref/sequences.texi b/doc/lispref/sequences.texi
index e66f61d22d3..8bb1e9e5abf 100644
--- a/doc/lispref/sequences.texi
+++ b/doc/lispref/sequences.texi
@@ -542,10 +542,10 @@ the function @code{char-table-subtype}, described below.
 @item
 The subtype controls the number of @dfn{extra slots} in the
 char-table.  This number is specified by the subtype's
-@code{char-table-extra-slots} symbol property, which should be an
-integer between 0 and 10.  If the subtype has no such symbol property,
-the char-table has no extra slots.  @xref{Property Lists}, for
-information about symbol properties.
+@code{char-table-extra-slots} symbol property (@pxref{Symbol
+Properties}), whose value should be an integer between 0 and 10.  If
+the subtype has no such symbol property, the char-table has no extra
+slots.
 @end itemize
 
 @cindex parent of char-table
diff --git a/doc/lispref/symbols.texi b/doc/lispref/symbols.texi
index 326c6cd4ab2..d3e5c1f1574 100644
--- a/doc/lispref/symbols.texi
+++ b/doc/lispref/symbols.texi
@@ -13,8 +13,8 @@ as variables and as function names; see @ref{Variables}, and
 @ref{Functions}.  For the precise read syntax for symbols, see
 @ref{Symbol Type}.
 
-  You can test whether an arbitrary Lisp object is a symbol
-with @code{symbolp}:
+  You can test whether an arbitrary Lisp object is a symbol with
+@code{symbolp}:
 
 @defun symbolp object
 This function returns @code{t} if @var{object} is a symbol, @code{nil}
@@ -26,7 +26,7 @@ otherwise.
                                and property lists.
 * Definitions::              A definition says how a symbol will be used.
 * Creating Symbols::         How symbols are kept unique.
-* Property Lists::           Each symbol has a property list
+* Symbol Properties::        Each symbol has a property list
                                for recording miscellaneous information.
 @end menu
 
@@ -91,7 +91,7 @@ the contents of a symbol's function cell, use the function
 
   The property list cell normally should hold a correctly formatted
 property list.  To get a symbol's property list, use the function
-@code{symbol-plist}.  @xref{Property Lists}.
+@code{symbol-plist}.  @xref{Symbol Properties}.
 
   The function cell or the value cell may be @dfn{void}, which means
 that the cell does not reference any object.  (This is not the same
@@ -376,109 +376,34 @@ If @code{unintern} does delete a symbol, it returns @code{t}.  Otherwise
 it returns @code{nil}.
 @end defun
 
-@node Property Lists
-@section Property Lists
-@cindex property list
-@cindex plist
+@node Symbol Properties
+@section Symbol Properties
+@cindex symbol property
 
-  A @dfn{property list} (@dfn{plist} for short) is a list of paired
-elements.  Each of the pairs associates a property name (usually a
-symbol) with a property or value.
+  A symbol may possess any number of @dfn{symbol properties}, which
+can be used to record miscellaneous information about the symbol.  For
+example, when a symbol has a @code{risky-local-variable} property with
+a non-@code{nil} value, that means the variable which the symbol names
+is a risky file-local variable (@pxref{File Local Variables}).
 
-  Every symbol has a cell that stores a property list (@pxref{Symbol
-Components}).  This property list is used to record information about
-the symbol, such as its variable documentation and the name of the
-file where it was defined.
-
-  Property lists can also be used in other contexts.  For instance,
-you can assign property lists to character positions in a string or
-buffer.  @xref{Text Properties}.
-
-  The property names and values in a property list can be any Lisp
-objects, but the names are usually symbols.  Property list functions
-compare the property names using @code{eq}.  Here is an example of a
-property list, found on the symbol @code{progn} when the compiler is
-loaded:
-
-@example
-(lisp-indent-function 0 byte-compile byte-compile-progn)
-@end example
-
-@noindent
-Here @code{lisp-indent-function} and @code{byte-compile} are property
-names, and the other two elements are the corresponding values.
+  Each symbol's properties and property values are stored in the
+symbol's property list cell (@pxref{Symbol Components}), in the form
+of a property list (@pxref{Property Lists}).
 
 @menu
-* Plists and Alists::           Comparison of the advantages of property
-                                  lists and association lists.
-* Symbol Plists::               Functions to access symbols' property lists.
-* Other Plists::                Accessing property lists stored elsewhere.
+* Symbol Plists::        Accessing symbol properties.
+* Standard Properties::  Standard meanings of symbol properties.
 @end menu
 
-@node Plists and Alists
-@subsection Property Lists and Association Lists
-@cindex plist vs. alist
-@cindex alist vs. plist
-
-@cindex property lists vs association lists
-  Association lists (@pxref{Association Lists}) are very similar to
-property lists.  In contrast to association lists, the order of the
-pairs in the property list is not significant since the property names
-must be distinct.
-
-  Property lists are better than association lists for attaching
-information to various Lisp function names or variables.  If your
-program keeps all such information in one association list, it will
-typically need to search that entire list each time it checks for an
-association for a particular Lisp function name or variable, which
-could be slow.  By contrast, if you keep the same information in the
-property lists of the function names or variables themselves, each
-search will scan only the length of one property list, which is
-usually short.  This is why the documentation for a variable is
-recorded in a property named @code{variable-documentation}.  The byte
-compiler likewise uses properties to record those functions needing
-special treatment.
-
-  However, association lists have their own advantages.  Depending on
-your application, it may be faster to add an association to the front of
-an association list than to update a property.  All properties for a
-symbol are stored in the same property list, so there is a possibility
-of a conflict between different uses of a property name.  (For this
-reason, it is a good idea to choose property names that are probably
-unique, such as by beginning the property name with the program's usual
-name-prefix for variables and functions.)  An association list may be
-used like a stack where associations are pushed on the front of the list
-and later discarded; this is not possible with a property list.
-
 @node Symbol Plists
-@subsection Property List Functions for Symbols
-
-@defun symbol-plist symbol
-This function returns the property list of @var{symbol}.
-@end defun
-
-@defun setplist symbol plist
-This function sets @var{symbol}'s property list to @var{plist}.
-Normally, @var{plist} should be a well-formed property list, but this is
-not enforced.  The return value is @var{plist}.
+@subsection Accessing Symbol Properties
 
-@example
-(setplist 'foo '(a 1 b (2 3) c nil))
-     @result{} (a 1 b (2 3) c nil)
-(symbol-plist 'foo)
-     @result{} (a 1 b (2 3) c nil)
-@end example
-
-For symbols in special obarrays, which are not used for ordinary
-purposes, it may make sense to use the property list cell in a
-nonstandard fashion; in fact, the abbrev mechanism does so
-(@pxref{Abbrevs}).
-@end defun
+  The following functions can be used to access symbol properties.
 
 @defun get symbol property
-This function finds the value of the property named @var{property} in
-@var{symbol}'s property list.  If there is no such property, @code{nil}
-is returned.  Thus, there is no distinction between a value of
+This function returns the value of the property named @var{property}
+in @var{symbol}'s property list.  If there is no such property, it
+returns @code{nil}.  Thus, there is no distinction between a value of
 @code{nil} and the absence of the property.
 
 The name @var{property} is compared with the existing property names
@@ -487,12 +412,6 @@ using @code{eq}, so any object is a legitimate property.
 See @code{put} for an example.
 @end defun
 
-@defun function-get symbol property
-This function is identical to @code{get}, except that if @var{symbol}
-is the name of a function alias, it looks in the property list of the
-symbol naming the actual function.  @xref{Defining Functions}.
-@end defun
-
 @defun put symbol property value
 This function puts @var{value} onto @var{symbol}'s property list under
 the property name @var{property}, replacing any previous property value.
@@ -510,69 +429,132 @@ The @code{put} function returns @var{value}.
 @end example
 @end defun
 
-@node Other Plists
-@subsection Property Lists Outside Symbols
-
-  These functions are useful for manipulating property lists
-not stored in symbols:
-
-@defun plist-get plist property
-This returns the value of the @var{property} property stored in the
-property list @var{plist}.  It accepts a malformed @var{plist}
-argument.  If @var{property} is not found in the @var{plist}, it
-returns @code{nil}.  For example,
-
-@example
-(plist-get '(foo 4) 'foo)
-     @result{} 4
-(plist-get '(foo 4 bad) 'foo)
-     @result{} 4
-(plist-get '(foo 4 bad) 'bad)
-     @result{} nil
-(plist-get '(foo 4 bad) 'bar)
-     @result{} nil
-@end example
-@end defun
-
-@defun plist-put plist property value
-This stores @var{value} as the value of the @var{property} property in
-the property list @var{plist}.  It may modify @var{plist} destructively,
-or it may construct a new list structure without altering the old.  The
-function returns the modified property list, so you can store that back
-in the place where you got @var{plist}.  For example,
-
-@example
-(setq my-plist '(bar t foo 4))
-     @result{} (bar t foo 4)
-(setq my-plist (plist-put my-plist 'foo 69))
-     @result{} (bar t foo 69)
-(setq my-plist (plist-put my-plist 'quux '(a)))
-     @result{} (bar t foo 69 quux (a))
-@end example
+@defun symbol-plist symbol
+This function returns the property list of @var{symbol}.
 @end defun
 
-  You could define @code{put} in terms of @code{plist-put} as follows:
+@defun setplist symbol plist
+This function sets @var{symbol}'s property list to @var{plist}.
+Normally, @var{plist} should be a well-formed property list, but this is
+not enforced.  The return value is @var{plist}.
 
 @example
-(defun put (symbol prop value)
-  (setplist symbol
-            (plist-put (symbol-plist symbol) prop value)))
+(setplist 'foo '(a 1 b (2 3) c nil))
+     @result{} (a 1 b (2 3) c nil)
+(symbol-plist 'foo)
+     @result{} (a 1 b (2 3) c nil)
 @end example
 
-@defun lax-plist-get plist property
-Like @code{plist-get} except that it compares properties
-using @code{equal} instead of @code{eq}.
+For symbols in special obarrays, which are not used for ordinary
+purposes, it may make sense to use the property list cell in a
+nonstandard fashion; in fact, the abbrev mechanism does so
+(@pxref{Abbrevs}).
 @end defun
 
-@defun lax-plist-put plist property value
-Like @code{plist-put} except that it compares properties
-using @code{equal} instead of @code{eq}.
+@defun function-get symbol property
+This function is identical to @code{get}, except that if @var{symbol}
+is the name of a function alias, it looks in the property list of the
+symbol naming the actual function.  @xref{Defining Functions}.
 @end defun
 
-@defun plist-member plist property
-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
+@node Standard Properties
+@subsection Standard Symbol Properties
+
+  Here, we list the symbol properties which are used for special
+purposes in Emacs.  In the following table, whenever we say ``the
+named function'', that means the function whose name is the relevant
+symbol; similarly for ``the named variable'' etc.
+
+@table @code
+@item :advertised-binding
+This property value specifies the preferred key binding, when showing
+documentation, for the named function.  @xref{Keys in Documentation}.
+
+@item char-table-extra-slots
+The value, if non-@code{nil}, specifies the number of extra slots in
+the named char-table type.  @xref{Char-Tables}.
+
+@itemx customized-face
+@item face-defface-spec
+@itemx saved-face
+@itemx theme-face
+These properties are used to record a face's standard, saved,
+customized, and themed face specs.  Do not set them directly; they are
+managed by @code{defface} and related functions.  @xref{Defining
+Faces}.
+
+@itemx customized-value
+@itemx saved-value
+@item standard-value
+@itemx theme-value
+These properties are used to record a customizable variable's standard
+value, saved value, customized-but-unsaved value, and themed values.
+Do not set them directly; they are managed by @code{defcustom} and
+related functions.  @xref{Variable Definitions}.
+
+@item disabled
+If the value is non-@code{nil}, the named function is disabled as a
+command.  @xref{Disabling Commands}.
+
+@item face-documentation
+The value stores the documentation string of the named face.  This is
+normally set automatically by @code{defface}.  @xref{Defining Faces}.
+
+@item history-length
+The value, if non-@code{nil}, specifies the maximum minibuffer history
+length for the named history list variable.  @xref{Minibuffer
+History}.
+
+@item interactive-form
+The value is an interactive form for the named function.  Normally,
+you should not set this directly; use the @code{interactive} special
+form instead.  @xref{Interactive Call}.
+
+@item menu-enable
+The value is an expression for determining whether the named menu item
+should be enabled in menus.  @xref{Simple Menu Items}.
+
+@item mode-class
+If the value is @code{special}, the named major mode is ``special''.
+@xref{Major Mode Conventions}.
+
+@item permanent-local
+If the value is non-@code{nil}, the named variable is a buffer-local
+variable whose value should not be reset when changing major modes.
+@xref{Creating Buffer-Local}.
+
+@item permanent-local-hook
+If the value is non-@code{nil}, the named function should not be
+deleted from the local value of a hook variable when changing major
+modes.  @xref{Setting Hooks}.
+
+@item pure
+This property is used internally to mark certain named functions for
+byte compiler optimization.  Do not set it.
+
+@item risky-local-variable
+If the value is non-@code{nil}, the named variable is considered risky
+as a file-local variable.  @xref{File Local Variables}.
+
+@item safe-function
+If the value is non-@code{nil}, the named function is considered
+generally safe for evaluation.  @xref{Function Safety}.
+
+@item safe-local-eval-function
+If the value is non-@code{nil}, the named function is safe to call in
+file-local evaluation forms.  @xref{File Local Variables}.
+
+@item safe-local-variable
+The value specifies a function for determining safe file-local values
+for the named variable.  @xref{File Local Variables}.
+
+@item side-effect-free
+A non-@code{nil} value indicates that the named function is free of
+side-effects, for determining function safety (@pxref{Function
+Safety}) as well as for byte compiler optimizations.  Do not set it.
+
+@item variable-documentation
+If non-@code{nil}, this specifies the named vaariable's documentation
+string.  This is normally set automatically by @code{defvar} and
+related functions.  @xref{Defining Faces}.
+@end table
diff --git a/doc/lispref/variables.texi b/doc/lispref/variables.texi
index dfde3c45c04..2168bd5af05 100644
--- a/doc/lispref/variables.texi
+++ b/doc/lispref/variables.texi
@@ -1423,7 +1423,6 @@ disappear after doing its job and will not interfere with the
 subsequent major mode.  @xref{Hooks}.
 @end defvar
 
-@c Emacs 19 feature
 @cindex permanent local variable
 A buffer-local variable is @dfn{permanent} if the variable name (a
 symbol) has a @code{permanent-local} property that is non-@code{nil}.