**topical media & game development**

object-oriented programming

# Instructor's Guide: Abstract Data Types

#### Rationale

This chapter presents an introduction to
the theoretical foundations of abstract
data types.
In particular, an algebraic treatment is
given of abstract data types defined by equational theories.
We then extend this approach to include objects
with dynamic state changes.
We start this chapter with a discussion of the notion of types
and reflect on how types affect object-oriented
programming.
At the end of the chapter, a distinction is made between
a syntactic, semantic and operational
interpretation of types.

#### Hints

The viewpoint expressed in this chapter,
and more fully worked out in the two
subsequent chapters, may be characterized
by the phrase

*types as constraints*.
In presenting the material you may need to emphasize
the intuition underlying this viewpoint.
Put simply, the more information you have, the more
precisely a type is defined, and the more restricted
the set of elements that belong to the type.
Subtyping means narrowing down by providing more
information.

#### Project assignments

The notion of data abstraction gives rise
to a wealth of possibly interesting assignments.

For example, one may think of
exploring

- algebraic object specification methods,

including proof-theoretical aspects
with respect to invariance properties,
as outlined in chapter [refinement].

Another interesting area of investigation is

- the relation between modules, classes and types.

In particular, do we need modules when we have classes,
and how may they be integrated with classes with
respect to visibility and protection?

#### Comments

Section

[Algebra], covering an algebraic approach to the
specification of abstract data types and objects,
may be too demanding for students with no background
in mathematical logic and set theory.

(C) Æliens
04/09/2009

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