3 - VDMTools Lite

Summary

Aims

The aim of this chapter is to introduce VDMTools Lite, the development environment for VDM-SL models. This is done by providing a “hands-on” tour of the tool's functionality using the alarm example introduced in Chapter 2. This chapter should enable the reader to use VDMTools Lite for exercises in the remaining part of this book.

Introduction

Models in VDM are formal in the sense that their semantics are very precisely described. This formality makes it possible to analyse models in order to confirm or refute claims about them. Such an analysis often reveals gaps in the understanding of the system, allowing these to be resolved before an expensive commitment is made to program code. The process of analysing claims about systems modelled in this way is termed validation and is discussed in greater depth in Chapter 10.

Software tools play an important role in supporting validation. This book is accompanied by an educational version of the VDM-SL version of VDMTools, called VDMTools Lite, that provides most of the functionality of the commercial tool.

This chapter introduces VDMTools Lite as a preparation for the examples and exercises of later chapters. It takes the form of a tour through the facilities for performing syntax checking, type checking, integrity checking, testing and debugging of models, using the alarm example which was presented in Chapter 2. The reader is encouraged to use the VDMTools Lite or the full VDM-SL version of VDMTools for all the exercises in this and subsequent chapters.

VDMTools Lite exists for several operating system platforms including Windows, Linux and MacOS.