References :: introduction
It's easy to manage and manipulate complex nested data structures in perl, but only if you use references. And there is just one overriding principle:
"Perl does no implicit referencing or dereferencing. When a scalar is holding a reference, it always behaves as a simple scalar. It doesn't magically start being an array or hash or subroutine; you have to tell it explicitly to do so, by dereferencing it."