Session Summary: Object Orientation and Exception Handling for Ada

The session started with a consensus view from the group about the powerful contribution potential that exceptions can offer to the construction of reliable systems. Ada has rightly deserved the reputation of being prime language support for the development of systems with reliability characteristics. One would therefore expect that the language should take special care to address the needs of the reliable system community. Yet, the group noted, the design of the language enhancements added to Ada 95 held a narrow view of exceptions, which were seemingly regarded as simple-minded aid for rudimentary program debugging. The few, timid enhancements made to exceptions in the language indeed had the merit of clarifying the notions of exception identity and exception occurrence. Nonetheless, the language revision apparently privileged the view of exceptions as a low-cost mechanism for fairly high-level error logging. As a regrettable result, exceptions are still not integrated with the typing model of the language. A rapid scrutiny of the workshop submissions allowed the group to gather consensus on three major limitations with the current model of exceptions: