The SIMULA Foundation

Abstract

This chapter is a short introduction to the highlights of SIMULA. It is not meant to be exhaustive: it merely aims to give the reader with little or no prior knowledge of SIMULA enough understanding to follow through the later chapters on DEMOS. Full accounts of SIMULA are found in Birtwistle et al. [11] and Rohlfing [12]. The central new ideas in SIMULA are those of the OBJECT and of the CONTEXT. An OBJECT is used in SIMULA to mirror the characteristics and behaviour of a major component in the system under description. For example, a boat in a harbour simulation or a furnace in a steel mill simulation. Objects with similar characteristics and the same behaviour pattern have the same single definition called a CLASS DECLARATION. A CONTEXT is roughly a library of object definitions common to one particular topic, e.g. a HARBOUR context may contain class declarations for boats, cranes, tugs, the tide, etc., and a TRAFFIC context may contain class declarations for cars, trucks, etc. Once defined, a context serves as a library of predefined building blocks.