Multilayer dereferencing question

[Anonymous Monk]

I'm messing around with dereferencing arrays, and was curious why the following portion of this code involving the hash doesn't work:

my @array1 = (
'abc',
'def',
'ghi',
'jkl'
);

my $s1 = \@array1;
my $s2 = \$s1; 

my %hash = ( 'key' => $s1 );
my $hash_s = \%hash;

print(@$$s2); # works
print(@$$hash{'key'}); # doesn't work

If I remove the @, both lines will print out an array reference. I understand how to make it work, just curious about if there's something with hashes that makes them work a little differently? Thanks

[Anonymous Monk]

Sorry I copied it over wrong, the print statement should be  print(@$$hash_s{'key'});

[choroba]

@$$hash_s{key} is a shorter way of writing

@{ ${ $hash_s } }{key}

but you need

@{ ${ $hash_s }{key} }

which is usually written

@{ $hash_s->{key} }

as the arrow operator is more readable than the circumfix dereference.