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From: worley@compass.com (Dale Worley)
Newsgroups: comp.lang.perl
Subject: What I want in regular expressions
Message-ID: <1990Jun27.144859.15573@uvaarpa.Virginia.EDU>
Date: 27 Jun 90 14:48:59 GMT
Sender: mmdf@uvaarpa.Virginia.EDU (Uvaarpa Mail System)
Reply-To: worley@compass.com
Organization: The Internet
Lines: 33

There are a number of features that could be put into regexp matching
that would make life easier:

	a \- b

Match any string which matches a but is not matched (in its entirity)
by b.

	\- b

Match the null string if what follows this position is not matched by
b.

	a \: b \; c

Match b but only if its left context is matched by a and its right
context is matched by c.  This would be useful for simplifying s/ / /
constructions:

	s/(a)b(c)/\1d\2/

becomes

	s/a\:b\;c/d/

Probably, a should be included in $` and c in $'.

How hard would this be to do?

Dale Worley		Compass, Inc.			worley@compass.com
--
If people think nature is their friend, then they sure don't need an enemy.
        --Kurt Vonnegut