use warnings;
use strict;
use Data::Dump;

my @testarray = ([10,20],[30,40]);

dd "A", @testarray;
foreach (@testarray) {
	dd "B", @testarray;
	while ( <DATA> ) {
		dd "C", @testarray;
	}
	dd "D", @testarray;
}
dd "E", @testarray;

__DATA__
hello
world

##</code><code>##

("A", [10, 20], [30, 40])
("B", [10, 20], [30, 40])
("C", "hello\n", [30, 40])
("C", "world\n", [30, 40])
("D", undef, [30, 40])
("B", undef, [30, 40])
("D", undef, undef)
("E", undef, undef)