Fix behavior of with-temp-buffer-window (Bug#16816, Bug#17007).

[gnu-emacs] / doc / lispref / help.texi

diff --git a/doc/lispref/help.texi b/doc/lispref/help.texi
index 9fe069b84d05772efa493b6ca2c876f5333c4e7b..9a763b60938dd25408fa57cb58e9cdd80b9dad39 100644 (file)
--- a/doc/lispref/help.texi
+++ b/doc/lispref/help.texi
@@ -1,6 +1,6 @@
 @c -*-texinfo-*-
 @c This is part of the GNU Emacs Lisp Reference Manual.
 @c -*-texinfo-*-
 @c This is part of the GNU Emacs Lisp Reference Manual.

-@c Copyright (C) 1990-1995, 1998-1999, 2001-2013 Free Software
+@c Copyright (C) 1990-1995, 1998-1999, 2001-2014 Free Software

 @c Foundation, Inc.
 @c See the file elisp.texi for copying conditions.
 @node Documentation
 @c Foundation, Inc.
 @c See the file elisp.texi for copying conditions.
 @node Documentation


@@ -10,8 +10,13 @@
   GNU Emacs has convenient built-in help facilities, most of which
 derive their information from documentation strings associated with
 functions and variables.  This chapter describes how to access
   GNU Emacs has convenient built-in help facilities, most of which
 derive their information from documentation strings associated with
 functions and variables.  This chapter describes how to access

-documentation strings in Lisp programs.  @xref{Documentation Tips},
-for how to write good documentation strings.
+documentation strings in Lisp programs.
+
+  The contents of a documentation string should follow certain
+conventions.  In particular, its first line should be a complete
+sentence (or two complete sentences) that briefly describes what the
+function or variable does.  @xref{Documentation Tips}, for how to
+write good documentation strings.

 
   Note that the documentation strings for Emacs are not the same thing
 as the Emacs manual.  Manuals have their own source files, written in
 
   Note that the documentation strings for Emacs are not the same thing
 as the Emacs manual.  Manuals have their own source files, written in


@@ -40,78 +45,48 @@ Help, emacs, The GNU Emacs Manual}.
 @cindex string, writing a doc string
 
   A documentation string is written using the Lisp syntax for strings,
 @cindex string, writing a doc string
 
   A documentation string is written using the Lisp syntax for strings,

-with double-quote characters surrounding the text of the string.  This
-is because it really is a Lisp string object.  The string serves as
-documentation when it is written in the proper place in the definition
-of a function or variable.  In a function definition, the documentation
-string follows the argument list.  In a variable definition, the
-documentation string follows the initial value of the variable.
-
-  When you write a documentation string, make the first line a
-complete sentence (or two complete sentences) that briefly describes
-what the function or variable does.  Some commands, such as
-@code{apropos}, show only the first line of a multi-line documentation
-string.  Also, you should not indent the second line of a
-documentation string, if it has one, because that looks odd when you
-use @kbd{C-h f} (@code{describe-function}) or @kbd{C-h v}
-(@code{describe-variable}) to view the documentation string.  There
-are many other conventions for documentation strings; see
-@ref{Documentation Tips}.
-
-  Documentation strings can contain several special text sequences,
-referring to key bindings which are looked up in the current keymaps
-when the user views the documentation.  This allows the help commands
-to display the correct keys even if a user rearranges the default key
+with double-quote characters surrounding the text.  It is, in fact, an
+actual Lisp string.  When the string appears in the proper place in a
+function or variable definition, it serves as the function's or
+variable's documentation.
+
+@cindex @code{function-documentation} property
+  In a function definition (a @code{lambda} or @code{defun} form), the
+documentation string is specified after the argument list, and is
+normally stored directly in the function object.  @xref{Function
+Documentation}.  You can also put function documentation in the
+@code{function-documentation} property of a function name
+(@pxref{Accessing Documentation}).
+
+@cindex @code{variable-documentation} property
+  In a variable definition (a @code{defvar} form), the documentation
+string is specified after the initial value.  @xref{Defining
+Variables}.  The string is stored in the variable's
+@code{variable-documentation} property.
+
+@cindex @file{DOC} (documentation) file
+  Sometimes, Emacs does not keep documentation strings in memory.
+There are two such circumstances.  Firstly, to save memory, the
+documentation for preloaded functions and variables (including
+primitives) is kept in a file named @file{DOC}, in the directory
+specified by @code{doc-directory} (@pxref{Accessing Documentation}).
+Secondly, when a function or variable is loaded from a byte-compiled
+file, Emacs avoids loading its documentation string (@pxref{Docs and
+Compilation}).  In both cases, Emacs looks up the documentation string
+from the file only when needed, such as when the user calls @kbd{C-h
+f} (@code{describe-function}) for a function.
+
+  Documentation strings can contain special @dfn{key substitution
+sequences}, referring to key bindings which are looked up only when
+the user views the documentation.  This allows the help commands to
+display the correct keys even if a user rearranges the default key

 bindings.  @xref{Keys in Documentation}.
 
   In the documentation string of an autoloaded command
 bindings.  @xref{Keys in Documentation}.
 
   In the documentation string of an autoloaded command

-(@pxref{Autoload}), these special text sequences have an additional
-special effect: they cause @kbd{C-h f} (@code{describe-function}) on
-the command to trigger autoloading.  (This is needed for correctly
-setting up the hyperlinks in the @file{*Help*} buffer).
-
-@vindex emacs-lisp-docstring-fill-column
-  Emacs Lisp mode fills documentation strings to the width
-specified by @code{emacs-lisp-docstring-fill-column}.
-
-  Exactly where a documentation string is stored depends on how its
-function or variable was defined or loaded into memory:
-
-@itemize @bullet
-@item
-@kindex function-documentation
-When you define a function (@pxref{Lambda Expressions}, and
-@pxref{Function Documentation}), the documentation string is stored in
-the function definition itself.  You can also put function
-documentation in the @code{function-documentation} property of a
-function name.  That is useful for function definitions which can't
-hold a documentation string, such as keyboard macros.
-
-@item
-@kindex variable-documentation
-When you define a variable with a @code{defvar} or related form
-(@pxref{Defining Variables}), the documentation is stored in the
-variable's @code{variable-documentation} property.
-
-@cindex @file{DOC-@var{version}} (documentation) file
-@item
-To save memory, the documentation for preloaded functions and
-variables (including primitive functions and autoloaded functions) is
-not kept in memory, but in the file
-@file{emacs/etc/DOC-@var{version}}, where @var{version} is the Emacs
-version number (@pxref{Version Info}).
-
-@item
-When a function or variable is loaded from a byte-compiled file during
-the Emacs session, its documentation string is not loaded into memory.
-Instead, Emacs looks it up in the byte-compiled file as needed.
-@xref{Docs and Compilation}.
-@end itemize
-
-@noindent
-Regardless of where the documentation string is stored, you can
-retrieve it using the @code{documentation} or
-@code{documentation-property} function, described in the next section.
+(@pxref{Autoload}), these key-substitution sequences have an
+additional special effect: they cause @kbd{C-h f} on the command to
+trigger autoloading.  (This is needed for correctly setting up the
+hyperlinks in the @file{*Help*} buffer.)

 
 @node Accessing Documentation
 @section Access to Documentation Strings
 
 @node Accessing Documentation
 @section Access to Documentation Strings


@@ -123,18 +98,20 @@ most often used to look up the documentation strings of variables, for
 which @var{property} is @code{variable-documentation}.  However, it
 can also be used to look up other kinds of documentation, such as for
 customization groups (but for function documentation, use the
 which @var{property} is @code{variable-documentation}.  However, it
 can also be used to look up other kinds of documentation, such as for
 customization groups (but for function documentation, use the

-@code{documentation} command, below).
+@code{documentation} function, below).

 
 

-If the value recorded in the property list refers to a documentation
-string stored in a @file{DOC-@var{version}} file or a byte-compiled
-file, it looks up that string and returns it.  If the property value
-isn't @code{nil}, isn't a string, and doesn't refer to text in a file,
-then it is evaluated as a Lisp expression to obtain a string.
+If the property value refers to a documentation string stored in the
+@file{DOC} file or a byte-compiled file, this function looks up that
+string and returns it.

 
 

-The last thing this function does is pass the string through
-@code{substitute-command-keys} to substitute actual key bindings
-(@pxref{Keys in Documentation}).  However, it skips this step if
-@var{verbatim} is non-@code{nil}.
+If the property value isn't @code{nil}, isn't a string, and doesn't
+refer to text in a file, then it is evaluated as a Lisp expression to
+obtain a string.
+
+Finally, this function passes the string through
+@code{substitute-command-keys} to substitute key bindings (@pxref{Keys
+in Documentation}).  It skips this step if @var{verbatim} is
+non-@code{nil}.

 
 @smallexample
 @group
 
 @smallexample
 @group


@@ -161,16 +138,18 @@ ordinary functions.
 If @var{function} is a symbol, this function first looks for the
 @code{function-documentation} property of that symbol; if that has a
 non-@code{nil} value, the documentation comes from that value (if the
 If @var{function} is a symbol, this function first looks for the
 @code{function-documentation} property of that symbol; if that has a
 non-@code{nil} value, the documentation comes from that value (if the

-value is not a string, it is evaluated).  If @var{function} is not a
-symbol, or if it has no @code{function-documentation} property, then
-@code{documentation} extracts the documentation string from the actual
-function definition, reading it from a file if called for.
+value is not a string, it is evaluated).
+
+If @var{function} is not a symbol, or if it has no
+@code{function-documentation} property, then @code{documentation}
+extracts the documentation string from the actual function definition,
+reading it from a file if called for.

 
 

-Finally, unless @var{verbatim} is non-@code{nil}, it calls
-@code{substitute-command-keys} so as to return a value containing the
-actual (current) key bindings.
+Finally, unless @var{verbatim} is non-@code{nil}, this function calls
+@code{substitute-command-keys}.  The result is the documentation
+string to return.

 
 

-The function @code{documentation} signals a @code{void-function} error
+The @code{documentation} function signals a @code{void-function} error

 if @var{function} has no function definition.  However, it is OK if
 the function definition has no documentation string.  In that case,
 @code{documentation} returns @code{nil}.
 if @var{function} has no function definition.  However, it is OK if
 the function definition has no documentation string.  In that case,
 @code{documentation} returns @code{nil}.


@@ -181,7 +160,6 @@ This function returns the documentation string of @var{face} as a
 face.
 @end defun
 
 face.
 @end defun
 

-@c Wordy to prevent overfull hboxes.  --rjc 15mar92

 Here is an example of using the two functions, @code{documentation} and
 @code{documentation-property}, to display the documentation strings for
 several symbols in a @file{*Help*} buffer.
 Here is an example of using the two functions, @code{documentation} and
 @code{documentation-property}, to display the documentation strings for
 several symbols in a @file{*Help*} buffer.


@@ -296,12 +274,12 @@ memory in the function definitions and variable property lists.
 Emacs reads the file @var{filename} from the @file{emacs/etc} directory.
 When the dumped Emacs is later executed, the same file will be looked
 for in the directory @code{doc-directory}.  Usually @var{filename} is
 Emacs reads the file @var{filename} from the @file{emacs/etc} directory.
 When the dumped Emacs is later executed, the same file will be looked
 for in the directory @code{doc-directory}.  Usually @var{filename} is

-@code{"DOC-@var{version}"}.
+@code{"DOC"}.

 @end defun
 
 @defvar doc-directory
 This variable holds the name of the directory which should contain the
 @end defun
 
 @defvar doc-directory
 This variable holds the name of the directory which should contain the

-file @code{"DOC-@var{version}"} that contains documentation strings for
+file @code{"DOC"} that contains documentation strings for

 built-in and preloaded functions and variables.
 
 In most cases, this is the same as @code{data-directory}.  They may be
 built-in and preloaded functions and variables.
 
 In most cases, this is the same as @code{data-directory}.  They may be


@@ -314,6 +292,7 @@ without actually installing it.  @xref{Definition of data-directory}.
 @cindex documentation, keys in
 @cindex keys in documentation strings
 @cindex substituting keys in documentation
 @cindex documentation, keys in
 @cindex keys in documentation strings
 @cindex substituting keys in documentation

+@cindex key substitution sequence

 
   When documentation strings refer to key sequences, they should use the
 current, actual key bindings.  They can do so using certain special text
 
   When documentation strings refer to key sequences, they should use the
 current, actual key bindings.  They can do so using certain special text


@@ -670,14 +649,17 @@ This function returns the name of the help buffer, which is normally
 @file{*Help*}; if such a buffer does not exist, it is first created.
 @end defun
 
 @file{*Help*}; if such a buffer does not exist, it is first created.
 @end defun
 

+@vindex help-window-select

 @defmac with-help-window buffer-name body@dots{}
 @defmac with-help-window buffer-name body@dots{}

-This macro evaluates the @var{body} forms, inserting any output they
-produce into a buffer named @var{buffer-name} like
-@code{with-output-to-temp-buffer} (@pxref{Temporary Displays}).
-(Usually, @var{buffer-name} should be the value returned by the
-function @code{help-buffer}.)  It also puts the specified buffer into
-Help mode and displays a message telling the user how to quit and
-scroll the help window.
+This macro evaluates @var{body} like @code{with-output-to-temp-buffer}
+(@pxref{Temporary Displays}), inserting any output produced by its forms
+into a buffer named @var{buffer-name}.  (Usually, @var{buffer-name}
+should be the value returned by the function @code{help-buffer}.)  It
+also puts the specified buffer into Help mode and displays a message
+telling the user how to quit and scroll the help window.  It selects the
+help window if the current value of the user option
+@code{help-window-select} has been set accordingly.  It returns the last
+value in @var{body}.

 @end defmac
 
 @defun help-setup-xref item interactive-p
 @end defmac
 
 @defun help-setup-xref item interactive-p