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From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: how long is a {0,m} match?
Message-ID: <8999@jpl-devvax.JPL.NASA.GOV>
Date: 3 Aug 90 21:06:41 GMT
References: <12170008@hpccc.HP.COM>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 23

In article <12170008@hpccc.HP.COM> weisberg@hpccc.HP.COM (Len Weisberg) writes:
: If there is some general principle about longest match, 
: it seems to break when 0 repetitions match, but only when
: the match is not at the start of the string.
: 
: Does this make sense?   Is it a bug?

Yes, it makes sense, and no, it isn't a bug.

The longest match rule is subordinate to two other rules:

	1. Find the leftmost match.

	2. Given 1, find the first alternative that matches.

	3. Given 1 and 2, find the longest match.

(Rules 2 and 3 apply recursively inside parentheses.)

Any item that can match 0 or more times will do so at the beginning of
a string if the first thing in the string isn't a match.

Larry