Provided by Paul McJones (mcjones@src.dec.com)

Sorted, dynamically growing table with REF keys and values whose
internal representation is a balanced binary tree.

The entries can be enumerated in ascending or descending key
order in linear time.  The worst-case time for Get, Put, or Delete
is proportional to the log of the number of entries in the table.

The current implementation uses 2-3-4 trees.

Index: sorted tables of REFs; tables, sorted



