Thanks, I've modified my code to use this, but surprisingly perl is dumping core (5.005_03 on FreeBSD and 5.6.1 on Solaris). This is a different problem, but I'm really surprised it's happening. Does anyone know why? Here's some code that reproduces the problem:

#!/usr/bin/perl -Tw

use strict;
use Benchmark;

my @array;
foreach (1..1000) {
    push @array, 1 + int rand 199;
}
my @start = (0, @array);
my @end = (@array, 0);
my @middle = @array;
splice(@middle, 500, 0, 0);

timethese(1000, {
    'grep_middle' => sub {
        my $found = 0;
        grep {$_ == 0 and $found = 1 and last} @middle;
    },
    'foreach_middle' => sub {
        my $found = 0;
        foreach (@middle) {
            $_ == 0 and $found = 1 and last;
        }
    },
    'hash_middle' => sub {
        my $found = 0;
        my %hash = map { $_ => undef } @middle;
        $found = 1 if exists $hash{0};
    }
});
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