The only problem with hashes (and hashes of hashes) is that they are seen as "advanced" and noone talks about them until way to late, when the programmer already needs to use... composite data structures. In Perl you (as usual) have to make these for yourself using hashes.

I remember learning Perl. Until someone mentioned hashes when I asked for data structures, I thought that there was no such thing in Perl! The next, mountain like, hurdle was the syntax for dereferencing complex data structures (and subs returning e.g. hashrefs).

Explain these concepts by example and you don't have a problem.

/J