The Windows equivalent of @code{HOME} is the @dfn{user-specific
application data directory}. The actual location depends on the
Windows version; typical values are @file{C:\Documents and
-Settings\@var{username}\Application Data} on Windows 2000/XP/2K3,
-@file{C:\Users\@var{username}\AppData\Roaming} on Windows
-Vista/7/2008, and either @file{C:\WINDOWS\Application Data} or
+Settings\@var{username}\Application Data} on Windows 2000 up to XP,
+@file{C:\Users\@var{username}\AppData\Roaming} on Windows Vista and
+later, and either @file{C:\WINDOWS\Application Data} or
@file{C:\WINDOWS\Profiles\@var{username}\Application Data} on Windows
9X/ME@. If this directory does not exist or cannot be accessed, Emacs
falls back to @file{C:\} as the default value of @code{HOME}.
A symbol is a sequence of one or more symbol-constituent characters.
A symbol-constituent character is a character whose syntax is either
@samp{w} or @samp{_}. @samp{\_<} matches at the beginning of the
-buffer only if a symbol-constituent character follows.
+buffer only if a symbol-constituent character follows. As with words,
+the syntax table determines which characters are symbol-constituent.
@item \_>
matches the empty string, but only at the end of a symbol. @samp{\_>}
Searches in Emacs by default ignore the case of the text they are
searching through, if you specify the search string in lower case.
Thus, if you specify searching for @samp{foo}, then @samp{Foo} and
-@samp{foo} also match. Regexps, and in particular character sets,
+@samp{fOO} also match. Regexps, and in particular character sets,
behave likewise: @samp{[ab]} matches @samp{a} or @samp{A} or @samp{b}
or @samp{B}. This feature is known as @dfn{case folding}, and it is
supported in both incremental and non-incremental search modes.
as well as to literal string search. The effect ceases if you delete
the upper-case letter from the search string. The variable
@code{search-upper-case} controls this: if it is non-@code{nil} (the
-default), an upper-case character in the search string make the search
-case-sensitive; setting it to @code{nil} disables this effect of
-upper-case characters.
+default), an upper-case character in the search string makes the
+search case-sensitive; setting it to @code{nil} disables this effect
+of upper-case characters.
@vindex case-fold-search
If you set the variable @code{case-fold-search} to @code{nil}, then
surrounded by word boundaries.
@xref{Replacement and Lax Matches}, for details about
-case-sensitivity in replace commands.
+case-sensitivity and character folding in replace commands.
@node Regexp Replace
@subsection Regexp Replacement
both.
Inside such an expression, you can use some special sequences.
-@samp{\&} and @samp{\@var{n}} refer here, as usual, to the entire
-match as a string, and to a submatch as a string. @var{n} may be
-multiple digits, and the value of @samp{\@var{n}} is @code{nil} if
-subexpression @var{n} did not match. You can also use @samp{\#&} and
-@samp{\#@var{n}} to refer to those matches as numbers (this is valid
-when the match or submatch has the form of a numeral). @samp{\#} here
-too stands for the number of already-completed replacements.
+@samp{\&} and @samp{\@var{d}} refer here, as usual, to the entire
+match as a string, and to a submatch as a string. @var{d} may be
+multiple digits, and the value of @samp{\@var{d}} is @code{nil} if the
+@var{d}'th parenthesized grouping did not match. You can also use
+@samp{\#&} and @samp{\#@var{d}} to refer to those matches as numbers
+(this is valid when the match or submatch has the form of a numeral).
+@samp{\#} here too stands for the number of already-completed
+replacements.
Repeating our example to exchange @samp{x} and @samp{y}, we can thus
do it also this way: