use warnings;
use strict;
use Benchmark qw(cmpthese);

my $str = "Just Another Perl Hacker";

print join " ", do_mapstr (), "\n";
print join " ", do_substr (), "\n";
print join " ", do_regex (), "\n";
print "\n";

cmpthese (-1,
        {
		mapstr => \&do_mapstr,
        substr => \&do_substr,
        regex => \&do_regex,
        }
    );


sub do_mapstr {
    return map substr($str,$_-3,3),(3..length $str);
}


sub do_substr {
    my @parts;
    
    push @parts, substr $str, $_, 3 for 0 .. length ($str) - 3;
    return @parts;
}


sub do_regex {
    return $str =~ /(?=(...))/g;
}