use strict;
use warnings;
use Perl6::Say;
use Data::Dumper qw/Dumper/;

my $t_order = [];
my $nt_order = [];
my @class = qw(5 4 3 6 1);
say "sort leftof (@class): " . join ":", (sort {sort_leftof($a, $b, $t_order, $nt_order)} @class);

sub sort_leftof {
	my $x1			= shift;
	my $x2			= shift;
	my $t_order		= shift;
	my $nt_order	= shift;
	
	if( $x1 < 500 and $x2 < 500 ) {
		$x1 < $x2;
	}

} # /sort_leftof