my %hash;
tie( %hash, "Tie::Hash::Stack" );

print defined( %hash ) ? "ok" : "not ok";

##</code><code>##

my %hash;
tie( %hash, "Tie::Hash::Stack" );

print ( %hash ) ? "ok" : "not ok";

##</code><code>##

my %hash;
my $obj = tie( %hash, "Tie::Hash::Stack" );

print defined( $obj ) ? "ok" : "not ok";
# or simply $obj ? "ok" : "not ok";