#! 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;
    ],
};

__END__
C:\test>junk30
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 2000022) line 1.
600001
Subroutine count redefined at (eval 2000023) line 1.
600001
Subroutine count redefined at (eval 2000026) line 1.
600001
            (warning: too few iterations for a reliable count)

                  Rate many_evals       loop   one_eval
many_evals 3.76e-002/s         --       -97%       -98%
loop            1.17/s      3002%         --       -52%
one_eval        2.41/s      6303%       106%         --