(Reading from Files): Document that null bytes force no-conversion when visiting

[bpt/emacs.git] / doc / lispref / strings.texi

diff --git a/doc/lispref/strings.texi b/doc/lispref/strings.texi
index 37c19fc..0b53a7a 100644 (file)
--- a/doc/lispref/strings.texi
+++ b/doc/lispref/strings.texi
@@ -1,7 +1,7 @@
 @c -*-texinfo-*-
 @c This is part of the GNU Emacs Lisp Reference Manual.
 @c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2001,
-@c   2002, 2003, 2004, 2005, 2006, 2007, 2008  Free Software Foundation, Inc.
+@c   2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009  Free Software Foundation, Inc.
 @c See the file elisp.texi for copying conditions.
 @setfilename ../../info/strings
 @node Strings and Characters, Lists, Numbers, Top
@@ -39,7 +39,8 @@ keyboard character events.
 
   Characters are represented in Emacs Lisp as integers;
 whether an integer is a character or not is determined only by how it is
-used.  Thus, strings really contain integers.
+used.  Thus, strings really contain integers.  @xref{Character Codes},
+for details about character representation in Emacs.
 
   The length of a string (like any array) is fixed, and cannot be
 altered once the string exists.  Strings in Lisp are @emph{not}
@@ -54,16 +55,13 @@ and @code{aset} (@pxref{Array Functions}).
 
   There are two text representations for non-@acronym{ASCII} characters in
 Emacs strings (and in buffers): unibyte and multibyte (@pxref{Text
-Representations}).  An @acronym{ASCII} character always occupies one byte in a
-string; in fact, when a string is all @acronym{ASCII}, there is no real
-difference between the unibyte and multibyte representations.
-For most Lisp programming, you don't need to be concerned with these two
-representations.
+Representations}).  For most Lisp programming, you don't need to be
+concerned with these two representations.
 
-  Sometimes key sequences are represented as strings.  When a string is
-a key sequence, string elements in the range 128 to 255 represent meta
-characters (which are large integers) rather than character
-codes in the range 128 to 255.
+  Sometimes key sequences are represented as unibyte strings.  When a
+unibyte string is a key sequence, string elements in the range 128 to
+255 represent meta characters (which are large integers) rather than
+character codes in the range 128 to 255.
 
   Strings cannot hold characters that have the hyper, super or alt
 modifiers; they can hold @acronym{ASCII} control characters, but no other
@@ -103,8 +101,8 @@ otherwise.
 @end defun
 
 @defun string-or-null-p object
-This function returns @code{t} if @var{object} is a string or nil,
-@code{nil} otherwise.
+This function returns @code{t} if @var{object} is a string or
+@code{nil}.  It returns @code{nil} otherwise.
 @end defun
 
 @defun char-or-string-p object
@@ -272,7 +270,9 @@ printed form is with @code{format} (@pxref{Formatting Strings}) or
 For information about other concatenation functions, see the
 description of @code{mapconcat} in @ref{Mapping Functions},
 @code{vconcat} in @ref{Vector Functions}, and @code{append} in @ref{Building
-Lists}.
+Lists}.  For concatenating individual command-line arguments into a
+string to be used as a shell command, see @ref{Shell Arguments,
+combine-and-quote-strings}.
 @end defun
 
 @defun split-string string &optional separators omit-nulls
@@ -357,6 +357,10 @@ practice:
 (split-string "ooo" "\\|o+" t)
      @result{} ("o" "o" "o")
 @end example
+
+If you need to split a string that is a shell command, where
+individual arguments could be quoted, see @ref{Shell Arguments,
+split-string-and-unquote}.
 @end defun
 
 @defvar split-string-default-separators