@c This is part of the Emacs manual.
-@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001, 2002,
-@c 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+@c Copyright (C) 1985-1987, 1993-1995, 1997, 2000-2011
+@c Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Search, Fixit, Display, Top
@chapter Searching and Replacement
@menu
-* Incremental Search:: Search happens as you type the string.
-* Nonincremental Search:: Specify entire string and then search.
-* Word Search:: Search for sequence of words.
-* Regexp Search:: Search for match for a regexp.
-* Regexps:: Syntax of regular expressions.
-* Regexp Backslash:: Regular expression constructs starting with `\'.
-* Regexp Example:: A complex regular expression explained.
-* Search Case:: To ignore case while searching, or not.
-* Replace:: Search, and replace some or all matches.
-* Other Repeating Search:: Operating on all matches for some regexp.
+* Incremental Search:: Search happens as you type the string.
+* Nonincremental Search:: Specify entire string and then search.
+* Word Search:: Search for sequence of words.
+* Regexp Search:: Search for match for a regexp.
+* Regexps:: Syntax of regular expressions.
+* Regexp Backslash:: Regular expression constructs starting with `\'.
+* Regexp Example:: A complex regular expression explained.
+* Search Case:: To ignore case while searching, or not.
+* Replace:: Search, and replace some or all matches.
+* Other Repeating Search:: Operating on all matches for some regexp.
@end menu
@node Incremental Search
@node Isearch Yank
@subsection Isearch Yanking
- Within incremental search, you can use @kbd{C-w} and @kbd{C-y} to grab
-text from the buffer into the search string. This makes it convenient
-to search for another occurrence of text at point.
+ Within incremental search, @kbd{C-y} (@code{isearch-yank-kill})
+copies text from the kill ring into the search string. It uses the
+same text that @kbd{C-y}, outside of incremental search, would
+normally yank into the buffer. @kbd{Mouse-2} in the echo area does
+the same. @xref{Yanking}.
- @kbd{C-w} copies the character or word after point and adds it to
-the search string, advancing point over it. (The decision, whether to
-copy a character or a word, is heuristic.)
+ @kbd{C-w} (@code{isearch-yank-word-or-char}) grabs the next
+character or word at point, and adds it to the search string. This is
+convenient for searching for another occurrence of the text at point.
+(The decision, whether to copy a character or a word, is heuristic.)
- @kbd{C-y} is similar to @kbd{C-w} but copies all the rest of the
-current line into the search string. If point is already at the end
-of a line, it grabs the entire next line. If the search is currently
-case-insensitive, both @kbd{C-y} and @kbd{C-w} convert the text they
-copy to lower case, so that the search remains case-insensitive.
+ Similarly, @kbd{M-s C-e} (@code{isearch-yank-line}) grabs the rest
+of the current line, and adds it to the search string. If point is
+already at the end of a line, it grabs the entire next line.
+
+ If the search is currently case-insensitive, both @kbd{C-w} and
+@kbd{M-s C-e} convert the text they copy to lower case, so that the
+search remains case-insensitive.
@kbd{C-M-w} and @kbd{C-M-y} modify the search string by only one
character at a time: @kbd{C-M-w} deletes the last character from the
@kbd{M-e} and to type @kbd{C-f} at the end of the search string in the
minibuffer.
- The character @kbd{M-y} copies text from the kill ring into the
-search string. It uses the same text that @kbd{C-y} would yank.
-@kbd{Mouse-2} in the echo area does the same. @xref{Yanking}.
-
@node Isearch Scroll
@subsection Scrolling During Incremental Search
These run the commands @code{word-search-forward} and
@code{word-search-backward} respectively.
- A nonincremental word search differs slightly from the incremental
-version in the way it finds a match: the last word in the search
-string must be an exact match for a whole word. In an incremental
-word search, the last word in the search string can match part of a
-word; this allows the matching to proceed incrementally as you type.
+ Incremental and nonincremental word searches differ slightly in the
+way they find a match. In a nonincremental word search, the last word
+in the search string must exactly match a whole word. In an
+incremental word search, the matching is more lax: the last word in
+the search string can match part of a word, so that the matching
+proceeds incrementally as you type. This additional laxity does not
+apply to the lazy highlight, which always matches whole words.
@node Regexp Search
@section Regular Expression Search
-@cindex regular expression
-@cindex regexp
+@cindex regexp search
+@cindex search for a regular expression
A @dfn{regular expression} (or @dfn{regexp} for short) is a pattern
that denotes a class of alternative strings to match. GNU Emacs
@node Regexps
@section Syntax of Regular Expressions
@cindex syntax of regexps
+@cindex regular expression
+@cindex regexp
This manual describes regular expression features that users
-typically want to use. There are additional features that are
-mainly used in Lisp programs; see @ref{Regular Expressions,,,
-elisp, The Emacs Lisp Reference Manual}.
+typically use. @xref{Regular Expressions,,, elisp, The Emacs Lisp
+Reference Manual}, for additional features used mainly in Lisp
+programs.
Regular expressions have a syntax in which a few characters are
special constructs and the rest are @dfn{ordinary}. An ordinary
-character is a simple regular expression which matches that same
-character and nothing else. The special characters are @samp{$},
-@samp{^}, @samp{.}, @samp{*}, @samp{+}, @samp{?}, @samp{[}, and
-@samp{\}. The character @samp{]} is special if it ends a character
-alternative (see later). The character @samp{-} is special inside a
-character alternative. Any other character appearing in a regular
-expression is ordinary, unless a @samp{\} precedes it. (When you use
-regular expressions in a Lisp program, each @samp{\} must be doubled,
-see the example near the end of this section.)
+character matches that same character and nothing else. The special
+characters are @samp{$^.*+?[\}. The character @samp{]} is special if
+it ends a character alternative (see later). The character @samp{-}
+is special inside a character alternative. Any other character
+appearing in a regular expression is ordinary, unless a @samp{\}
+precedes it. (When you use regular expressions in a Lisp program,
+each @samp{\} must be doubled, see the example near the end of this
+section.)
For example, @samp{f} is not a special character, so it is ordinary, and
therefore @samp{f} is a regular expression that matches the string
also match @samp{F} and @samp{O}, but we consider this a generalization
of ``the same string,'' rather than an exception.)
- Any two regular expressions @var{a} and @var{b} can be concatenated. The
-result is a regular expression which matches a string if @var{a} matches
-some amount of the beginning of that string and @var{b} matches the rest of
-the string.@refill
-
- As a simple example, we can concatenate the regular expressions @samp{f}
-and @samp{o} to get the regular expression @samp{fo}, which matches only
-the string @samp{fo}. Still trivial. To do something nontrivial, you
-need to use one of the special characters. Here is a list of them.
+ Any two regular expressions @var{a} and @var{b} can be concatenated.
+The result is a regular expression which matches a string if @var{a}
+matches some amount of the beginning of that string and @var{b}
+matches the rest of the string. For example, concatenating the
+regular expressions @samp{f} and @samp{o} gives the regular expression
+@samp{fo}, which matches only the string @samp{fo}. Still trivial.
+To do something nontrivial, you need to use one of the special
+characters. Here is a list of them.
@table @asis
@item @kbd{.}@: @r{(Period)}
-is a special character that matches any single character except a newline.
-Using concatenation, we can make regular expressions like @samp{a.b}, which
-matches any three-character string that begins with @samp{a} and ends with
-@samp{b}.@refill
+is a special character that matches any single character except a
+newline. For example, the regular expressions @samp{a.b} matches any
+three-character string that begins with @samp{a} and ends with
+@samp{b}.
@item @kbd{*}
is not a construct by itself; it is a postfix operator that means to
-match the preceding regular expression repetitively as many times as
-possible. Thus, @samp{o*} matches any number of @samp{o}s (including no
-@samp{o}s).
+match the preceding regular expression repetitively any number of
+times, as many times as possible. Thus, @samp{o*} matches any number
+of @samp{o}s, including no @samp{o}s.
@samp{*} always applies to the @emph{smallest} possible preceding
expression. Thus, @samp{fo*} has a repeating @samp{o}, not a repeating
@item @kbd{+}
is a postfix operator, similar to @samp{*} except that it must match
-the preceding expression at least once. So, for example, @samp{ca+r}
-matches the strings @samp{car} and @samp{caaaar} but not the string
-@samp{cr}, whereas @samp{ca*r} matches all three strings.
+the preceding expression at least once. Thus, @samp{ca+r} matches the
+strings @samp{car} and @samp{caaaar} but not the string @samp{cr},
+whereas @samp{ca*r} matches all three strings.
@item @kbd{?}
-is a postfix operator, similar to @samp{*} except that it can match the
-preceding expression either once or not at all. For example,
-@samp{ca?r} matches @samp{car} or @samp{cr}; nothing else.
+is a postfix operator, similar to @samp{*} except that it can match
+the preceding expression either once or not at all. Thus, @samp{ca?r}
+matches @samp{car} or @samp{cr}, and nothing else.
@item @kbd{*?}, @kbd{+?}, @kbd{??}
@cindex non-greedy regexp matching
-are non-greedy variants of the operators above. The normal operators
-@samp{*}, @samp{+}, @samp{?} are @dfn{greedy} in that they match as
-much as they can, as long as the overall regexp can still match. With
-a following @samp{?}, they are non-greedy: they will match as little
-as possible.
+are non-@dfn{greedy} variants of the operators above. The normal
+operators @samp{*}, @samp{+}, @samp{?} match as much as they can, as
+long as the overall regexp can still match. With a following
+@samp{?}, they will match as little as possible.
Thus, both @samp{ab*} and @samp{ab*?} can match the string @samp{a}
and the string @samp{abbbb}; but if you try to match them both against
starting at the first @samp{a}, it does.
@item @kbd{\@{@var{n}\@}}
-is a postfix operator that specifies repetition @var{n} times---that
-is, the preceding regular expression must match exactly @var{n} times
-in a row. For example, @samp{x\@{4\@}} matches the string @samp{xxxx}
-and nothing else.
+is a postfix operator specifying @var{n} repetitions---that is, the
+preceding regular expression must match exactly @var{n} times in a
+row. For example, @samp{x\@{4\@}} matches the string @samp{xxxx} and
+nothing else.
@item @kbd{\@{@var{n},@var{m}\@}}
-is a postfix operator that specifies repetition between @var{n} and
-@var{m} times---that is, the preceding regular expression must match
-at least @var{n} times, but no more than @var{m} times. If @var{m} is
+is a postfix operator specifying between @var{n} and @var{m}
+repetitions---that is, the preceding regular expression must match at
+least @var{n} times, but no more than @var{m} times. If @var{m} is
omitted, then there is no upper limit, but the preceding regular
expression must match at least @var{n} times.@* @samp{\@{0,1\@}} is
equivalent to @samp{?}. @* @samp{\@{0,\@}} is equivalent to
@samp{*}. @* @samp{\@{1,\@}} is equivalent to @samp{+}.
@item @kbd{[ @dots{} ]}
-is a @dfn{character set}, which begins with @samp{[} and is terminated
-by @samp{]}. In the simplest case, the characters between the two
-brackets are what this set can match.
+is a @dfn{character set}, beginning with @samp{[} and terminated by
+@samp{]}.
-Thus, @samp{[ad]} matches either one @samp{a} or one @samp{d}, and
-@samp{[ad]*} matches any string composed of just @samp{a}s and @samp{d}s
-(including the empty string), from which it follows that @samp{c[ad]*r}
-matches @samp{cr}, @samp{car}, @samp{cdr}, @samp{caddaar}, etc.
+In the simplest case, the characters between the two brackets are what
+this set can match. Thus, @samp{[ad]} matches either one @samp{a} or
+one @samp{d}, and @samp{[ad]*} matches any string composed of just
+@samp{a}s and @samp{d}s (including the empty string). It follows that
+@samp{c[ad]*r} matches @samp{cr}, @samp{car}, @samp{cdr},
+@samp{caddaar}, etc.
You can also include character ranges in a character set, by writing the
starting and ending characters with a @samp{-} between them. Thus,
which matches any lower-case @acronym{ASCII} letter or @samp{$}, @samp{%} or
period.
-Note that the usual regexp special characters are not special inside a
-character set. A completely different set of special characters exists
-inside character sets: @samp{]}, @samp{-} and @samp{^}.
+You can also include certain special @dfn{character classes} in a
+character set. A @samp{[:} and balancing @samp{:]} enclose a
+character class inside a character alternative. For instance,
+@samp{[[:alnum:]]} matches any letter or digit. @xref{Char Classes,,,
+elisp, The Emacs Lisp Reference Manual}, for a list of character
+classes.
To include a @samp{]} in a character set, you must make it the first
character. For example, @samp{[]a]} matches @samp{]} or @samp{a}. To
word-constituent character.
@item \w
-matches any word-constituent character. The syntax table
-determines which characters these are. @xref{Syntax}.
+matches any word-constituent character. The syntax table determines
+which characters these are. @xref{Syntax Tables,, Syntax Tables,
+elisp, The Emacs Lisp Reference Manual}.
@item \W
matches any character that is not a word-constituent.
matches any character whose syntax is @var{c}. Here @var{c} is a
character that designates a particular syntax class: thus, @samp{w}
for word constituent, @samp{-} or @samp{ } for whitespace, @samp{.}
-for ordinary punctuation, etc. @xref{Syntax}.
+for ordinary punctuation, etc. @xref{Syntax Tables,, Syntax Tables,
+elisp, The Emacs Lisp Reference Manual}.
@item \S@var{c}
matches any character whose syntax is not @var{c}.
@var{c}.
@end table
- The constructs that pertain to words and syntax are controlled by the
-setting of the syntax table (@pxref{Syntax}).
+ The constructs that pertain to words and syntax are controlled by
+the setting of the syntax table. @xref{Syntax Tables,, Syntax Tables,
+elisp, The Emacs Lisp Reference Manual}.
@node Regexp Example
@section Regular Expression Example
- Here is an example of a regexp---the regexp that Emacs uses, by
-default, to recognize the end of a sentence, not including the
-following space (i.e., the variable @code{sentence-end-base}):
+ Here is an example of a regexp---similar to the regexp that Emacs
+uses, by default, to recognize the end of a sentence, not including
+the following space (i.e., the variable @code{sentence-end-base}):
@example
@verbatim
-[.?!][]\"'””)}]*
+[.?!][]\"')}]*
@end verbatim
@end example
command @code{expand-region-abbrevs} (@pxref{Expanding Abbrevs}).
@menu
-* Unconditional Replace:: Replacing all matches for a string.
-* Regexp Replace:: Replacing all matches for a regexp.
-* Replacement and Case:: How replacements preserve case of letters.
-* Query Replace:: How to use querying.
+* Unconditional Replace:: Replacing all matches for a string.
+* Regexp Replace:: Replacing all matches for a regexp.
+* Replacement and Case:: How replacements preserve case of letters.
+* Query Replace:: How to use querying.
@end menu
@node Unconditional Replace, Regexp Replace, Replace, Replace
If a match is split across lines, this command keeps all those lines.
@end table
-
-@ignore
- arch-tag: fd9d8e77-66af-491c-b212-d80999613e3e
-@end ignore