ob_state() - object lfun

The printing of inventories is controlled by the inv_list()
simul.  Clones of the same base file are normally printed
as one item, i.e. "Three blue swords".  However, if ob_state()
returns a nonzero value then only objects with the same value
for ob_state() are grouped.  An exception is the value -1,
which means never group this object with anything.

For example, container overrides it to depend on whether the
object has contents, and openable makes it so that open and
closed copies of the same object are printed separately in
rooms.

Beek - Nov 94