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From: merlyn@iwarp.intel.com (Randal Schwartz)
Newsgroups: comp.lang.perl
Subject: Re: fast grep?
Message-ID: <1990Oct17.044839.21709@iwarp.intel.com>
Date: 17 Oct 90 04:48:39 GMT
References: <1990Oct15.211219.8543@wrl.dec.com> <107211@convex.convex.com>
Sender: news@iwarp.intel.com
Reply-To: merlyn@iwarp.intel.com (Randal Schwartz)
Organization: Stonehenge; netaccess via Intel, Beaverton, Oregon, USA
Lines: 44
In-Reply-To: tchrist@convex.COM (Tom Christiansen)

In article <107211@convex.convex.com>, tchrist@convex (Tom Christiansen) writes:
| I still can't get it sufficently close to gnugrep to justify not running a
| system on gnugrep, but even so, there's nothing truly wrong with that.  I
| don't think Larry would have made popens and `foo` and system() so easy to
| get at if he didn't want you do use them.  Note that perl DOES beat
| everything except for gnugrep.  One of these days, I've got to see whether
| I can't vectorize any of the regexp stuff in perl...

Tom, go back and rerun your test with some slightly-more-optimal (I hope)
Perl code:

##################################################

#!/usr/bin/perl
# @ARGV = ('/usr/dict/words'); # for testing

undef $/; # enable maximal slurp mode
$* = 1; # ^$ work in searches with newlines
while (<>) {
	s/string/&cheat($`,$&,$')/eg;
}

sub cheat {
	local($left,$center,$right) = @_;
	print	substr($left,rindex($left,"\n")+1,99999),
		$center,
		substr($right,0,index($right,"\n")+1);
	$center;
}
		
##################################################

I think you were getting beat up on how often you went around the
while loop.  This code more closely matches what bmgrep is doing
inside.

(Yes, I actually tested this code for a change. :-)

print "Just another Perl hacker," # with theoretically enough time to write a good JAPH now, but still not doing it.... :-)
-- 
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III      |
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