From mboxrd@z Thu Jan  1 00:00:00 1970
Received: by archone.tamu.edu id <18888>; Sat, 1 Feb 1992 11:49:11 -0600
From: Byron Rakitzis <byron>
To: rc
Subject: Re: Match operator puzzlement
Message-Id: <92Feb1.114911cst.18888@archone.tamu.edu>
Date: Sat, 1 Feb 1992 11:49:02 -0600

Hm. I think I can do a little better than John here. The two following
sed substitutions should be ok to quote all characters in a word except
the metacharacters *, ? and [. The sed scripts will FAIL if there are
single quotes in the input, but I'm sure there's a way around that
problem too, I just haven't thought of a good way yet.

Anyway:

First you turn all single non-meta characters into quoted characters:
	
	sed 's/\([^[*?]\)/''\1''/g'	# using rc's quoting rules, of course.

e.g., "Hello?" goes to "'H''e''l''l''o'?"

Now you need to remove all '' sequences:

	sed 's/''''//g'

Now "Hello?" becomes "'Hello'?", which is exactly what we want. Not bad.

(BTW, I think I can prove by induction that this method works for all
strings which do not contain a ', but I do not have enough room
to write the proof here :-)

So the ~ example becomes something like:

	eval ~ 'subject' `{echo $funky_pattern | sed garbage}