Newsgroups: comp.editors
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!caen!hellgate.utah.edu!dog.ee.lbl.gov!elf.ee.lbl.gov!torek
From: torek@elf.ee.lbl.gov (Chris Torek)
Subject: Re: One user's editor wish list
Organization: Lawrence Berkeley Laboratory, Berkeley
References: <1991Feb22.134323.20410@scrumpy@.bnr.ca> <11032@dog.ee.lbl.gov> <1991Mar20.203401.26237@convex.com>
Message-ID: <11321@dog.ee.lbl.gov>
X-Local-Date: Fri, 22 Mar 91 01:15:49 PST
Reply-To: torek@elf.ee.lbl.gov (Chris Torek)
Date: Fri, 22 Mar 91 09:15:49 GMT

In article <1991Mar20.203401.26237@convex.com> tchrist@convex.COM
(Tom Christiansen) writes:
[in reply to my statement that `pure matchers' do not need \(...\)-style
 `remember' expressions]
>Untrue.  I use \references on the LHS of my substitutes, albeit
>infrequently.  For example:
>
>    prep '(\w+)\s+\1' *.ms
>
>to find repeated words on the same line in a document.

Such references are, strictly speaking, not regular expressions at
all.  I will not deny their utility, but they do make building a matcher
more difficult, which is why egrep, e.g., does not support this.
(Egrep builds a DFSA and then runs it, and egrep DFSAs cannot be made
to perform backreferences.)

The only reason I made the note in the first place was to prevent
someone else from objecting to the `same syntax for editor and matcher'
idea with the same note.  In other words, I was anticipating the claim:
`using the same syntax is stupid because ...' and had already rejected
it.

I take it this was unclear in my original article....
-- 
In-Real-Life: Chris Torek, Lawrence Berkeley Lab CSE/EE (+1 415 486 5427)
Berkeley, CA		Domain:	torek@ee.lbl.gov