May 26, 2018
Tie::RefHash - use references as hash keys
This module provides the ability to use references as hash keys if you first “tie” the hash variable to this module. Normally, only the keys of the tied hash itself are preserved as references; to use references as keys in hashes-of-hashes, use TieRefHashNestable, included as part of TieRefHash.
It is implemented using the standard perl TIEHASH interface. Please see the “tie” entry in perlfunc1 and perltie1 for more information.
The Nestable version works by looking for hash references being stored and converting them to tied hashes so that they too can have references as keys. This will happen without warning whenever you store a refer- ence to one of your own hashes in the tied hash.