Regions

[Hugh Hoover <heh>]

The smalltalk version of regions is now (essentially) complete.  Well, ok,
it's about done for discrete, linear regions, where we now have the following:

Heaper

  Region

    DiscreteRegion

	DiscreteInterval (implementation)

	DiscreteIntervalUnion (implementation)

	DiscreteSet (not done yet...)

The implementation of DiscreteInterval requires bounded regions.  It is
possible to alter for unbounded regions, but I won't do it unless we have
a concrete code requirement for it.  (in fact, i may just not do it :-)
Other limitations:
  The lambda operations (intersect, union ...) are limited to be between
DiscreteInterval and DiscreteInterval or:
DiscreteIntervalUnion and DiscreteInterval or:
DiscreteSet and DiscreteSet.
The implementation can be extended as required for better polymorphism.
(except that I think it is inappropriate to build a DiscreteSet of Integers
and then do operations with DiscreteIntervals or their Unions)

On to the Translation!
--Hugh