use strict;
use warnings;
use Benchmark qw/ cmpthese /;

my $R = 'R' x 42_000;
my $Q = 'Q' x 42_000;

sub foo {
    my $c = shift;

    pos $$c = 0;
    while ( 1 ) {
        next if $$c =~ /\G\d+R/;
        last unless $$c =~ /\w/g;
    }
}

sub foo_twostep {
    my $c = shift;

    pos $$c = 0;
    while ( 1 ) {
        next if ($$c =~ /\G\d+/ and $$c =~ /\GR/);
        last unless $$c =~ /\w/g;
    }
}

sub foo_asciidigits {
    my $c = shift;

    pos $$c = 0;
    while ( 1 ) {
        next if ($$c =~ /\G[0-9]/ and $$c =~ /\GR/);
        last unless $$c =~ /\w/g;
    }
}

cmpthese -3, { 
    R => sub { foo( \$R )},
    Q => sub { foo( \$Q )},
    R_twostep => sub { foo_twostep( \$R )},
    Q_twostep => sub { foo_twostep( \$Q )},
    R_ascii => sub { foo_asciidigits( \$R )},
    Q_ascii => sub { foo_asciidigits( \$Q )},
}

__END__
            Rate         Q Q_twostep R_twostep   R_ascii   Q_ascii         R
Q         1.99/s        --      -97%      -97%      -97%      -97%      -97%
Q_twostep 62.9/s     3054%        --       -1%       -7%       -8%      -17%
R_twostep 63.8/s     3101%        1%        --       -5%       -6%      -16%
R_ascii   67.5/s     3287%        7%        6%        --       -1%      -11%
Q_ascii   68.1/s     3319%        8%        7%        1%        --      -10%
R         76.0/s     3715%       21%       19%       13%       12%        --