Etyma:
		       A Framework for Modular Systems

				      by
			       Guruduth Banavar
				Gary Lindstrom
				 Douglas Orr

			       Technical Report
				 UUCS-94-035

			Department of Computer Science
			      University of Utah
			 Salt Lake City, UT 84112 USA

			       December 7, 1994

				   Abstract

	Modularity, i.e. support for the flexible construction, adaptation,
and combination of units of software, is an important goal in many systems.
In most cases, however, systems achieve only a few aspects of modularity.

	The problem can be traced to the inflexibility, or the limited view of
modularity taken by the underlying architecture of these systems.

	As a remedy, we show that the notions fundamental to object-oriented
programming, i.e. classes and inheritance, can be formulated as a simple
meta-level architecture that can be effectively reused in a wide variety of
contexts.  We have realized such an architecture as an O-O framework, and
constructed two significant and distinct completions of it.

	Systems based on this framework benefit not only from design and code
reuse, but also from the flexibility that the architecture offers.  In
addition, the architecture represents a unification of the fundamental ideas
of several similar but subtly different module systems.