[m-dev.] For review: Add implementation of reference types (global heap)

[Thomas Charles CONWAY]

Peter Schachte, you write:
> So why not allow a type to be defined abstractly, with no concrete type
> declaration at all, and only complain if some attempt is made to "look
> inside" an instance of that type?  This seems more in keeping with the
> overall style of Mercury. 

You can't tell if someone will look inside it or not very easily. You can't
tell until link time if someone tries to pass it to write for instance.
Just waiting for a link error if someone generates a reference to the
typeinfo for the type isn't all that good (I think this is the current
behaviour).

Thomas
-- 
Thomas Conway <conway at cs.mu.oz.au>
Nail here [] for new monitor.  )O+