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From: "Russ Cox" <rsc@swtch.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] "Intervalic
Date: Wed, 22 Feb 2006 16:47:23 -0500	[thread overview]
Message-ID: <5503884a2074c9ee5a97750065c15450@swtch.com> (raw)
In-Reply-To: <43fcd05c.uFuhwKCT62bRHZ92%yard-ape@telus.net>

> Sorry Bakul, you've lost me here.  These look like awk idioms with unix
> extended regular expressions forms, but I don't really understand them.
> In any case, even basic REs aren't available in Plan9 awk---right?

What he meant is that if you have a regular expression of the form
a{0,n} for any a, then you can replace that with a?a{0,n-1}, and 
similarly a{m,n} can be replaced with a{m-1,n-1}.  This gives you
an algorithm to convert a so-called intervalic regular expression
into a standard Plan 9 regular expression.

And awk does have standard Plan 9 regular expressions.

Russ



  reply	other threads:[~2006-02-22 21:47 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-02-22 18:33 yard-ape
2006-02-22 18:51 ` Russ Cox
2006-02-22 19:20   ` yard-ape
2006-02-23  2:24     ` geoff
2006-02-22 19:50 ` Bakul Shah
2006-02-22 20:58   ` yard-ape
2006-02-22 21:47     ` Russ Cox [this message]
2006-02-22 23:36       ` yard-ape
2006-02-22 18:50         ` Russ Cox
2006-02-23  0:05           ` yard-ape
2006-02-22 23:42         ` andrey mirtchovski

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