use strict;
use warnings;
use Benchmark qw(cmpthese);
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
sub closure_counter {
	my $count = shift;
	return sub { $count++ };
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
{package obj_counter;
	sub new {bless {count=>$_[1]};}
	sub count {return ($_[0]->{count})++}
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
my $obj_counter = obj_counter->new(3);
my $closure_counter = closure_counter(3);
cmpthese(1000,
	{
		obj_counter=>sub{$obj_counter->count()for 1..1000;},
		closure_counter=>sub{$closure_counter->()for 1..1000;}
	}
);

__END__

Benchmark: timing 1000 iterations of closure_counter, obj_counter...
closure_counter:  2 wallclock secs ( 2.58 usr +  0.00 sys =  2.58 CPU) @ 387.60/s (n=1000)
obj_counter:  5 wallclock secs ( 5.22 usr +  0.00 sys =  5.22 CPU) @ 191.57/s (n=1000)
                 Rate     obj_counter closure_counter
obj_counter     192/s              --            -51%
closure_counter 388/s            102%              --

##</code><code>##

use strict;
use warnings;
use Benchmark qw(cmpthese);
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
use IO::Dir;
sub closure_dir_iter {
	my $dir = IO::Dir->new(shift);
	return sub {
		my $fl = $dir->read();
		$dir->rewind() unless defined $fl;
		return $fl;
	};
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
{package obj_dir_iter;
	use IO::Dir;
	sub new {bless {dir=>IO::Dir->new($_[1])};}
	sub iter {
		my $fl = $_[0]->{dir}->read();
		$_[0]->{dir}->rewind() unless defined $fl;
		return $fl;
	}
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
my $obj_dir_iter = obj_dir_iter->new( "." );
my $closure_dir_iter = closure_dir_iter( "." );
cmpthese(500,
	{
		obj_dir_iter=>sub{while(defined(my $f = $obj_dir_iter->iter())){print "$f\n";}},
		closure_dir_iter=>sub{while(defined(my $f = $closure_dir_iter->())){print "$f\n";}}
	}
);


__END__

Benchmark: timing 2000 iterations of closure_dir_iter, obj_dir_iter...
obj_dir_iter:  1 wallclock secs ( 1.20 usr +  0.00 sys =  1.20 CPU) @ 1666.67/s (n=2000)
closure_dir_iter:  1 wallclock secs ( 1.10 usr +  0.00 sys =  1.10 CPU) @ 1818.18/s (n=2000)
                   Rate     obj_dir_iter closure_dir_iter
obj_dir_iter     1667/s               --              -8%
closure_dir_iter 1818/s               9%               --

##</code><code>##

use strict;
use warnings;
use Benchmark qw(cmpthese);
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
use constant PI => 3.14159265359;
sub closure_turtle {
	my ($h, $xy) = (0, [[0],[0]]); 	# h = heading (0 - north, 90 - east, etc)
	return sub { 
		$h = $h + (shift || 0);		# accumulative turns in degree
		my $d = shift || 0;			# distance
		$xy->[0][scalar(@{$xy->[0]})] = $d*sin(PI*$h/180) + $xy->[0][$#{@{$xy->[0]}}]; 
		$xy->[1][scalar(@{$xy->[1]})] = $d*cos(PI*$h/180) + $xy->[1][$#{@{$xy->[1]}}]; 
		return $xy;
	};
}
sub closure_koch {
	my ($turtle, $d, $level) = @_ ;
	if ($level==0) {$turtle->(0,$d); return 1;} 
	$turtle->(  0,0); closure_koch($turtle,$d/3,$level-1);
	$turtle->(-60,0); closure_koch($turtle,$d/3,$level-1);
	$turtle->(120,0); closure_koch($turtle,$d/3,$level-1);
	$turtle->(-60,0); closure_koch($turtle,$d/3,$level-1);
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
{package obj_turtle;
	use constant PI => 3.14159265359;
	sub new {return bless({h=>0,xy=>[[0],[0]]});}
	sub rt {$_[0]->{h}=$_[0]->{h}+$_[1];}			# right turn by x degrees
	sub fd {										# forward by x points
		my ($h, $xy, $d) = ($_[0]->{h}, $_[0]->{xy}, $_[1]);
		$xy->[0][scalar(@{$xy->[0]})] = $d*sin(PI*$h/180) + $xy->[0][$#{@{$xy->[0]}}]; 
		$xy->[1][scalar(@{$xy->[1]})] = $d*cos(PI*$h/180) + $xy->[1][$#{@{$xy->[1]}}]; 
		$_[0]->{xy} = $xy; return $xy;
	}
}
sub obj_koch {
	my ($turtle, $d, $level) = @_ ;
	if ($level==0) {$turtle->fd($d); return 1;} 
	$turtle->rt(  0); obj_koch($turtle, $d/3,$level-1);
	$turtle->rt(-60); obj_koch($turtle, $d/3,$level-1);
	$turtle->rt(120); obj_koch($turtle, $d/3,$level-1);
	$turtle->rt(-60); obj_koch($turtle, $d/3,$level-1);
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
my $obj_turtle = obj_turtle->new();
my $closure_turtle = closure_turtle();
cmpthese(100,
	{
		obj_turtle=>sub{for(0..2){$obj_turtle->rt(120); obj_koch($obj_turtle,170,4);}},
		closure_turtle=>sub{for(0..2){$closure_turtle->(120, 0); closure_koch($closure_turtle,170,4);}}
	}
);


__END__

Benchmark: timing 100 iterations of closure_turtle, obj_turtle...
closure_turtle:  6 wallclock secs ( 6.49 usr +  0.00 sys =  6.49 CPU) @ 15.41/s (n=100)
obj_turtle:  5 wallclock secs ( 4.99 usr +  0.00 sys =  4.99 CPU) @ 20.04/s (n=100)
                 Rate closure_turtle     obj_turtle
closure_turtle 15.4/s             --           -23%
obj_turtle     20.0/s            30%             --

##</code><code>##

# IF = %b.(%x.(%y.(b x) y))
$IF = sub { 
	my $b = shift;
	sub { 
		my $x = shift;
		sub { 
			my $y = shift;
			$b->($x)->($y);
		}
	}
}

# TRUE = %x.(%y.x)
$TRUE  = sub { 
	my $x = shift;
	sub { 
		my $y = shift;
		$x;
	}
}

# FALSE = %x.(%y.y)
$FALSE = sub { 
	my $x = shift;
	sub { 
		my $y = shift;
		$y;
	}
}

print $IF->($TRUE)->("then")->("else");   # prints "then"
print $IF->($FALSE)->("then")->("else");  # prints "else"