use strict;
use warnings;

use Benchmark qw( cmpthese );

my $OUTER = $ARGV[0] || -5;

my %tests = (
   'substr3' => '$a = substr($a, 1)',
   'substr4' => 'substr($a, 0, 1, "")',
   's///'    => '$a =~ s/.//s',
);

my %bench = map { $_ => "use strict;
                         use warnings;
                         for (1 .. our $inner) {
                            local our \$a = our \$arg;
                            $tests{$_} while length(\$a);
                         }
                        "
                }
              keys %tests;

for (
  [ '20,000', 80_000/20_000, 'a' x 20_000 ],
  [ '40,000', 80_000/40_000, 'a' x 40_000 ],
  [ '80,000', 80_000/80_000, 'a' x 80_000 ],
) {
   my $name         = $_->[0];
   local our $inner = $_->[1]
   local our $arg   = $_->[2];
   print("--------------------\n");
   print("$name\n");
   print("\n");
   cmpthese($OUTER, \%bench);
   print("\n");
}