TIECLASS Name: POP::Hash Desc: Implements a tied hash which contains a list of persistent objects, lazily, so that it at first just contains the objects' pids, but goes out and restores the object when it is accessed.

METHOD Name: POP::Hash::TIEHASH Desc: The tied hash constructor; takes the name of this collection in our parent, our parent and a hashref containing initial values.

METHOD Name: POP::Hash::FETCH Desc: Called whenever an element of the tied hash is accessed, this will restore the object if it hasn't already been, and then return it.

METHOD Name: POP::Hash::STORE Desc: Called whenever an element in the hash is set; Tells our parent to update persistence

METHOD Name: POP::Hash::EXISTS Desc: Called to see if a key exists in the hash.

METHOD Name: POP::Hash::DELETE Desc: Called to delete one key/value pair in the hash.

METHOD Name: POP::Hash::CLEAR Desc: Called to delete all key/value pairs in the hash.

METHOD Name: POP::Hash::FIRSTKEY Desc: Called when first iterating through the hash.

METHOD Name: POP::Hash::NEXTKEY Desc: Called when iterating through the hash.