Style question: deep inheritance

[David95038@aol.com (David Kristola)]

I am working on a MUD in Ada.  Inheritance lends
itself well to the problem domain, but after a few
levels of child types in child packages, i am
facing some ridiculously long names.  For
instance, portals are used to move from place to
place.  But they are a specialization of inanimate
objects (things), which are a specialization of
general things (entities), which are a
specialization of the parent class (which is used
to avoid the withing problem).  So, portal
specific operations can be found in
SAM.Entities.Things.Portals.  The three (and
counting) specializations of Portals are only
referenced once to initialize them and let them
register themselves into the system.  I could use
renames to flatten out the majority of references
(package SAM.Portals renames
SAM.Entities.Things.Portals;), but you can't
inherit from a rename, so the actual children are
still deeply nested.  The long package names
usually mean long file names.  This could become a
portability problem.

I'm interested in how other people have dealt with
this problem, or suggestions for how i might deal
with it.

Thanks,
--djk