A Fully Object-Oriented Exception Handling System: Rationale and Smalltalk Implementation

This paper motivates and presents the specification and the implementation of an exception handling system for an dynamically typed object-oriented language. A full object-oriented representation of exceptions and handlers, a meta-object protocol to handle using either termination or resumption makes the system powerful as well as extendible and solves various exception handling issues. Three kind of dynamic scope handlers (expression handlers, class handlers and default ones) make it possible to define reusable and fault-tolerant software modules. The implementation of the system is readable and simple to understand because achieved entirely in Objectworks Smalltalk, thanks to the reflective facilities of this language.