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From: ram-ashwin@YALE.ARPA (Ashwin Ram)
Newsgroups: comp.emacs
Subject: Re: (treat-as-single-undo)
Message-ID: <8709081530.AA24182@ATHENA.CS.YALE.EDU>
Date: Tue, 8-Sep-87 11:30:47 EDT
Article-I.D.: ATHENA.8709081530.AA24182
Posted: Tue Sep  8 11:30:47 1987
Date-Received: Wed, 9-Sep-87 04:36:25 EDT
Sender: daemon@eddie.MIT.EDU
Lines: 24

>    Often, I would like to 'chunk' a large group of changes as a single 'undo'
>    action. E.g. if I replace-regexp several lines, I'd like to be able to
>    'undo' the lot of them, not each one.

I don't know about chunking undoes in general, but for the replace-regexp
case, simply replace your use of:

        (replace-regexp regexp to-string)

by the following:

        (while (re-search-forward pattern)
               (replace-match replacement t))

This chunk of code will undo in one step, whereas replace-regexp undoes each
replacement one by one.  The second form has the additional advantage that
you can use the optional arguments to re-search-forward and replace-match if
you want to.

-- Ashwin Ram --

ARPA:    Ram-Ashwin@cs.yale.edu
UUCP:    {decvax,linus,seismo}!yale!Ram-Ashwin
BITNET:  Ram@yalecs