#!/usr/bin/perl
use strict;
use warnings;
use Benchmark qw(cmpthese);

my $code = {
	while_index => sub { # BrowserUk
		local $_ = $::TESTSTRING;
		s{(?:[^\cH]\cH|^\cH)}{}g while 1+index $_, chr(8);
		$_;
	},
	altr_subst => sub { # smackdab
		local $_ = $::TESTSTRING;
		1 while s/(?:[^\cH]\cH|^\cH+)//g;
		$_;
	},
	noaltr_subst  => sub { # smackdab
		local $_ = $::TESTSTRING;
		s/^\cH+//;
		1 while s/[^\cH]\cH//g;
		$_;
	},
	sexeger_while => sub { # shenme
		local $_ = reverse $::TESTSTRING;
		s{\cH[^\cH]|\cH$}{}g  while 1+index $_, chr(8);
		scalar reverse $_;
	},
	true_sexeger => sub { # Aristotle
		local $_ = reverse $::TESTSTRING;
		s/(\cH+)(??{ '.{0,'.length($1).'}' })//g;
		scalar reverse $_;
	},
	substr => sub { # Aristotle
		local $_ = $::TESTSTRING;
		while(/([\b]+)/g) {
			my $len = 2 * length($1);
			substr($_, pos() - $len, $len, '');
		}
		$_;
	},
};

$::TESTSTRING = "\bthis is an\b correct\b\b\b usage\b";
print "\nBenchmarking length ", length($::TESTSTRING), "\n";
cmpthese(-5, $code);

$::TESTSTRING x= 100;
print "\nBenchmarking length ", length($::TESTSTRING), "\n";
cmpthese(-5, $code);

__END__