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bug#21995: Documentation omission for regular expressions
From: |
Eli Zaretskii |
Subject: |
bug#21995: Documentation omission for regular expressions |
Date: |
Mon, 23 Nov 2015 19:02:21 +0200 |
> Date: Mon, 23 Nov 2015 12:16:59 +0000
> From: jan <rtm443x@googlemail.com>
>
> \& used as a replacement will substitute in the entire matched
> pattern. For example, given text
>
> hello
>
> and search regexp \(.\) with replacement \&\& you get
>
> hheelloo
>
> I have not been able to find this \& option in the regular expression
> part of the emacs manual.
It's described in the node "Regexp Replace" (since it's only relevant
to replacing a matched regexp). Quote:
`M-x replace-regexp <RET> REGEXP <RET> NEWSTRING <RET>'
Replace every match for REGEXP with NEWSTRING.
In `replace-regexp', the NEWSTRING need not be constant: it can
refer to all or part of what is matched by the REGEXP. `\&' in
NEWSTRING stands for the entire match being replaced. `\D' in
NEWSTRING, where D is a digit, stands for whatever matched the Dth
parenthesized grouping in REGEXP. (This is called a "back reference".)
`\#' refers to the count of replacements already made in this command,
as a decimal number. In the first replacement, `\#' stands for `0'; in
the second, for `1'; and so on. For example,