Commit c118d09e authored by Richard M. Stallman's avatar Richard M. Stallman
Browse files

(Regexp Backslash, Regexp Example): New nodes split out of Regexps.

parent b95a0c80
2005-08-11 Richard M. Stallman <rms@gnu.org>
* tips.texi (Key Binding Conventions, Programming Tips, Warning Tips):
New nodes split out of Coding Conventions.
* searching.texi (Regular Expressions): Document re-builder.
* os.texi (Time Parsing): New node split out of Time Conversion.
* processes.texi (Misc Network, Network Feature Testing)
(Network Options, Make Network): New nodes split out of
Low-Level Network.
2005-08-09 Richard M. Stallman <rms@gnu.org>
* frames.texi (Geometry): New node, split from Size and Position.
......
......@@ -24,6 +24,8 @@ asks interactively which occurrences to replace.
* 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.
......@@ -669,20 +671,26 @@ has two functions: it quotes the special characters (including
Because @samp{\} quotes special characters, @samp{\$} is a regular
expression that matches only @samp{$}, and @samp{\[} is a regular
expression that matches only @samp{[}, and so on.
See the following section for the special constructs that begin
with @samp{\}.
@end table
Note: for historical compatibility, special characters are treated as
Note: for historical compatibility, special characters are treated as
ordinary ones if they are in contexts where their special meanings make no
sense. For example, @samp{*foo} treats @samp{*} as ordinary since there is
no preceding expression on which the @samp{*} can act. It is poor practice
to depend on this behavior; it is better to quote the special character anyway,
regardless of where it appears.@refill
regardless of where it appears.
@node Regexp Backslash
@section Backslash in Regular Expressions
For the most part, @samp{\} followed by any character matches only that
character. However, there are several exceptions: two-character
sequences starting with @samp{\} that have special meanings. The second
character in the sequence is always an ordinary character when used on
its own. Here is a table of @samp{\} constructs.
For the most part, @samp{\} followed by any character matches only
that character. However, there are several exceptions: two-character
sequences starting with @samp{\} that have special meanings. The
second character in the sequence is always an ordinary character when
used on its own. Here is a table of @samp{\} constructs.
@table @kbd
@item \|
......@@ -836,8 +844,11 @@ matches any character that does @emph{not} belong to category
The constructs that pertain to words and syntax are controlled by the
setting of the syntax table (@pxref{Syntax}).
Here is a complicated regexp. It is a simplified version of the
regexp that Emacs uses, by default, to recognize the end of a sentence
@node Regexp Example
@section Regular Expression Example
Here is a complicated regexp---a simplified version of the regexp
that Emacs uses, by default, to recognize the end of a sentence
together with any whitespace that follows. We show its Lisp syntax to
distinguish the spaces from the tab characters. In Lisp syntax, the
string constant begins and ends with a double-quote. @samp{\"} stands
......@@ -864,27 +875,6 @@ for Lisp syntax. In commands that use ordinary minibuffer input to
read a regexp, you would quote the @kbd{C-j} by preceding it with a
@kbd{C-q} to prevent @kbd{C-j} from exiting the minibuffer.
@ignore
@c I commented this out because it is missing vital information
@c and therefore useless. For instance, what do you do to *use* the
@c regular expression when it is finished? What jobs is this good for?
@c -- rms
@findex re-builder
@cindex authoring regular expressions
For convenient interactive development of regular expressions, you
can use the @kbd{M-x re-builder} command. It provides a convenient
interface for creating regular expressions, by giving immediate visual
feedback. The buffer from which @code{re-builder} was invoked becomes
the target for the regexp editor, which pops in a separate window. At
all times, all the matches in the target buffer for the current
regular expression are highlighted. Each parenthesized sub-expression
of the regexp is shown in a distinct face, which makes it easier to
verify even very complex regexps. (On displays that don't support
colors, Emacs blinks the cursor around the matched text, as it does
for matching parens.)
@end ignore
@node Search Case
@section Searching and Case
......
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