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From: muir@cae780.csi.com (David Muir Sharnoff)
Newsgroups: comp.lang.perl
Subject: Simplifying paths.  A hairy regex
Message-ID: <11249@cae780.csi.com>
Date: 2 Mar 91 06:17:25 GMT
Reply-To: muir@csi.com  (David Muir Sharnoff)
Organization: Comdisco Systems Inc., Foster City, CA
Lines: 33

It's 10pm, everyone else has gone home, I just have to 
share this...  The most twisted regex that I've had to build.

I wanted to get rid of extra junk from unix filenames.

To that end, I tranform:

	a//c            -> a/c
	a/./c           -> a/c
	a/c/.           -> a/c
	a/b/../c        -> a/c
	a/c/d/..        -> a/c

Note: I do not tranform //a/c -> /a/c as that would break Apollo filenames.

------------ perl starts here ----------
sub simplify 
{
	for $p (@_) {
		while($p =~ s!(/\.(/))|(^(.+/)/)|(/\.$)|([^/.]+/\.\./)|(/[^/.]+/\.\.$)!\2\4!) {;}
	}
}
------------ perl ends here ----------

Please let me know if I overlooked something...  This is
production code and I support it in-house.

$,= ' ';$japh = "Just/not/really/../../another/././perl/hacker,/./today/../."; while($japh =~ s!(/\.(/))|(^(.+/)/)|(/\.$)|([^/.]+/\.\./)|(/[^/.]+/\.\.$)!\2\4!) {;}; print (split(m,/+,,$japh))[1-4];

-- 
David Muir Sharnoff.			"RISC is about one year ahead"
muir@csi.com				(415) 358-3664 (415) 644-0441
Comdisco Systems Inc.  919 East Hillsdale Blvd, Foster City, CA 94404