From: "J.R. Mauro" <jrm8005@gmail.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: [9fans] Recursive structural expressions?
Date: Thu, 20 Aug 2009 13:52:37 -0400 [thread overview]
Message-ID: <3aaafc130908201052o3c8a6334v13350c18f78120d9@mail.gmail.com> (raw)
Has anyone given thought to recursive structural regular expressions?
I didn't see a way to do recursion from reading the paper and
experimenting.
The reason for recursion would be that instead of having hopped-up
regexes, we'd now have context-free expressions. Yacc needing tokens
makes doing CF things a pain, but I think if grep, sed, sam, etc
understood a simple CF expression language, we'd have something that
was (mathematically) more powerful.
One (perhaps silly) example is that you could see if your source code
had balanced parens/braces/brackets/tags in a jiffy, but other
examples include searching through records with complex structure.
I suppose it would likely be too slow, but would it cost anything when
it's not used?
next reply other threads:[~2009-08-20 17:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-20 17:52 J.R. Mauro [this message]
2009-08-20 19:53 ` erik quanstrom
2009-08-20 20:33 ` J.R. Mauro
2009-08-20 20:39 ` erik quanstrom
2009-08-20 21:14 ` J.R. Mauro
2009-08-20 21:26 ` erik quanstrom
2009-08-21 0:21 ` J.R. Mauro
2009-08-21 1:01 ` erik quanstrom
2009-08-21 1:14 ` Charles Forsyth
2009-08-22 1:10 ` J.R. Mauro
2009-08-23 19:59 ` Aharon Robbins
2009-08-23 21:27 ` Rob Pike
2009-08-21 13:58 ` J. R. Mauro
2009-08-21 14:24 ` Russ Cox
2009-08-21 14:57 ` J. R. Mauro
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