This idea has been superseded by the ideas described at (p3,mrc)

The diode directory is a mutable object that between mutations provides a mapping of a name onto a 32 bit number. Additions and deletions may be made to a diode directory. A name is just what a record collection thinks a name is. A diode directory comes with a hole-free factory that produces an associated object that maps a name to its 32 bit value.

DDF(0;SB,M,SB==>c;DD,DDRF)

DD is a diode directory and DDRF is the factory of associated directory readers.

Produces a directory reader DDR.

Design Notes:

While this can be built it does not support the following situation well:
1000 compartments and a shared facilities tree with 1000 sub directories.

The above solution requires a dd reader for each combination of compartment and sub directory. Thus 1000000 dd readers are potentially required. UGH! It is not even clear when to create them.