A Hierarchical Co-operative Exception Handling Mechanism

Abstract

One of the most dominant philosophies within programming disciplines is the philosophy of layered systems. In a layered system (or hierarchical system) the layers are thought of as each implementing an abstract machine on top of the lower layers. Such an abstract machine in turn implements utilities (e.g. data-structures and operations) to be used at higher layers.

This paper will focus on exception handling in block-structured systems (as a special case of layered systems). It will be argued that none of the existing programming language proposals for exception handling support secure and well-behaved termination of activities in a block-structured system. Moreover, it is argued that certain termination strategies within block-structured systems cannot be implemented using the existing proposals. As a result of this discussion and as a solution to the problems, a hierarchical, co-operative exception handling mechanism is proposed.