Number of buckets in the table. Automatically doubled if the table is
filled over 2/3-th.
NOTE: The number of buckets is a power of 2. Hash-table literature
claims prime numbers to provide a better distribution. Timing on the
SUN-SPARC station suggests this does ot compensate for the difference
between a division and a masking operation.
Which of the key and the value of an entry create a reference to the
object. The default is both. A table created with none
refers to neither, which is what a tool that monitors the object base
needs: it can hold objects without keeping them alive. Such a table does
not know when an entry dies, so the tool must remove entries itself, for
example from a class->freed_message.
Pass it as the second initialisation argument:
new(T, hash_table(@default, none))
