#! perl -slw
use strict;
use Benchmark qw[ cmpthese ];

cmpthese -1, {
    one_eval => q[
        my $t = 1;
        eval qq[ sub count { \$_[0] =~ tr[$t][$t] } ];
        my $c = 0;
        $c += count( $_ ) for 1 .. 1e6;
        print $c;
    ],
    many_evals => q[
        my $t = 1;
        my $c = 0;
        $c += eval qq[ \$_ =~ tr[$t][$t] ] for 1 .. 1e6;
        print $c;
    ],
    loop => q[
        my $t = 1;
        my $c = 0;
        for my $n ( 1 .. 1e6 ) {
            ++$c while $n =~ m[$t]g;
        }
        print $c;
    ],
    loop2 => q[
        my $t = 1;
        my $c = 0;
        for my $n ( 1 .. 1e6 ) {
            $c += () = $n =~ m[$t]g;
        }
        print $c;
    ],
};

__END__
C:\test>junk30
600001
600001
600001
            (warning: too few iterations for a reliable count)

600001
600001
600001
            (warning: too few iterations for a reliable count)

600001
600001
            (warning: too few iterations for a reliable count)

600001
Subroutine count redefined at (eval 2000028) line 1.
600001
Subroutine count redefined at (eval 2000029) line 1.
600001
Subroutine count redefined at (eval 2000032) line 1.
600001
            (warning: too few iterations for a reliable count)

                  Rate many_evals      loop2       loop   one_eval
many_evals 3.68e-002/s         --       -97%       -97%       -98%
loop2           1.06/s      2777%         --        -7%       -57%
loop            1.14/s      3006%         8%         --       -53%
one_eval        2.44/s      6515%       130%       113%         --