I'm using (attempting to use) PERL to build a representation
of an electrical system in a hash of arrays.
Taps (branches) off of the main line (trunk) need to use
names T1, T2, T3, etc.
Taps of taps need to be T1A, T1B, etc T2A, T2B etc.
Taps of taps of taps - T1A1, T1A2, etc T2B1, T2B3 etc.
Taps will be several layers deep.
How can I "autoincrement" in this way?