3 Lecture Series 2:
Programming-in-the-large in the Mjølner System

The purpose of this series of lectures is to present the constructs for programming-in-the-large in the Mjølner System. The BETA language does deliberately not include any facilities for modularization, encapsulation, separation of interface and implementation, etc. However, the Mjølner System includes a fragment system which makes modularization, encapsulation, separation of interface and implementation, separate compilation, etc. possible for BETA programs. Furthermore, this Lecture Series will present how exceptions can be dealt with in the BETA language.

3.1 Topics

• Overview of modularization, encapsulation and separation of interface and implementation
• Introduction of grammar-based program modularization
• The fragment system
  • Fragments and slots
  • Origin
  • Include
  • Body
• Modularization using the fragment system
• Encapsulation using the fragment system
• Separation of interface and implementation using the fragment system
• Exceptions
• Overview of language constructs
• Exception handling in BETA

3.2 Lectures

3.2.1 The Fragment System (Basics)

Readings: [MMN 93, chap. 17 (17.1)]

Notes: This lecture presents the general grammar-based approach to program modularization, and its realisation in the BETA fragment system.

It is important to emphasise, that the fragment system is orthogonal to the BETA language. Emphasis that the fragment system controls slots, fragment forms, fragment groups, and the binding of fragments to slots (and the visibility of these bindings).

3.2.2 The Fragment System (Advanced)

Readings: [MMN 93, chap. 17 (17.2-17.6)]

Notes: This lecture discusses the facilities for separating interface and implementation, for making abstract data structures, for creating program variants, etc.

3.2.3 Exceptional Computation and Overview of Language Constructs

Readings: [JLK84,87], [Borgida85]

Notes: Exception handling is an important part of programming large robust systems. This lecture will present the issues involved and a taxonomy for exception handling.

3.2.4 Exception Handling

Readings: [MMN 93, chap. 16]

Notes: Presentation the power of BETA, allowing exception handling to be handled within the language itself.