[ruby-talk:21719] Array and Hash mix-ins

Many thanks for all the informative answers to my last batch of
questions!

Now I've got another one... 

The Perl standard library contains some modules called Tie::Hash and
Tie::Array which ease the creation of hash-like and array-like objects.
Much like the Enumerable class in Ruby, these modules provide a great
deal of methods "for free", as long as the derived class implements a
few key methods on which all the others rely.  I'd find the equivalent
Ruby modules to be quite useful, if they existed.  Before I write them,
I wanted to know if anyone has already written them, or if the Array and
Hash classes themselves can be used for this purpose. In other words,
are most of the the Array and Hash methods implemented in terms of a
couple of basic methods which could be overridden?

thanks,

- Avdi Grimm