use strict;
use warnings;
use Tie::Cycle;

tie my $cycle, 'Tie::Cycle', [ 1..3,0,reverse (1..3),0 ];
$\=":stmt while\n";
print my $statement=$_ while ($_=$cycle)>0;
print defined($statement) ? "Defined" : "Notdefined";

$_="Do's pre-evaluation";

$\=":do{}while\n";
do { print my $do = $_ } while ($_=$cycle)>0;
eval 'print defined($do) ? "Defined" : "Notdefined";';
print $@ if $@;

$\=":stmt while 0\n";
print my $while="Test"	while 0;
print defined($while) ? "Defined" : "Notdefined";

$\=":stmt if\n";
print my $if="Test" if 0;
print defined($if) ? "Defined" : "Notdefined";

$\=":stmt for\n";
print my $for=$_ for 0;
print defined($for) ? "Defined" : "Notdefined";
__DATA__
1:stmt while
2:stmt while
3:stmt while
Notdefined:stmt while
Do's pre-evaluation:do{}while
3:do{}while
2:do{}while
1:do{}while
Global symbol "$do" requires explicit package name at (eval 1) line 1.
:do{}while
Notdefined:stmt while 0
Notdefined:stmt if
0:stmt for
Notdefined:stmt for