Object-oriented programming has, in recent years, become the most influential programming paradigm. It is widely ised in education and industry...

This paper is intended as an introduction to a broad range of ideas in object-oriented programming. Specifically, we introduce four modern programming languages that support object-oriented programming (Oberon-2, Modula-3, Sather and Self), and show how a simple application is coded in these languages. While each of these programming languages provide support for inheritance, dynamic dispatch, code reuse, and information hiding, they do so in very different ways and with varying levels of efficiency and simplicity. The use of a simple example, based on a common programming problem, facilitates our comparison. We have coded the application in all of these languages, including C++, and we compare the compile times, object code sizes, and run times of the available implementations. Implementations of all the languages compared and all of the programs we measure are available on the Internet. Ultimately, our goal is to encourage and facilitate programmers in understanding and exploring a variety of object-oriented programming languages

Dynamic binding in object-oriented languages is perhaps the most important semantic aspect of these languages. At the same time it can contribute to inefficiency and lack of robustness because it incurs lookup overheads on function calls and hinders the compiler determining the exact type of objects held in variables or returned by functions. This may, for instance, preclude inlining of small functions or attribute offset computation at compile time. Yet attribute accesses are the most frequently executed operations. As a result, to regain lost performance, OO programmers are tempted to break the encapsulation of classes or want explicit control over dynamic dispatch, trading off extensibility. In the implementation of parallel object-oriented languages the additional complication arises that object accesses may require more expensive remote memory accesses. Lookup at the call may be inappropriate if the code has to be executed on a different processor and there perhaps has a different...

While object-orientation has been widely accepted as an important programming paradigm, teaching object-orientation remains difficult. Experience reports suggest that some problems can be avoided by teaching object-orientation as the first language in an introductory course. However, other problems remain, in particular languages and environments are regularly criticised as unsuitable and overly complex. This thesis discusses aspects of object-oriented languages and environments that affect their suitability for first year teaching. General requirements for languages and environments are identified and used as a means to judge the suitability of the most popular systems in use today. The discussion shows that none of the currently available systems is suitable for object-oriented first year teaching. A new integrated software development environment and language called Blue is presented. Blue overcomes the problems identified and opens new possibilities for teaching and learning obje...

With the development of distributed object technologies and the overwhelming advent of the Web, an object-oriented data model for GIS/LIS is proposed, possessing significantly increasing importance and application, when moving from a static position to a distributed and heterogeneous view. The conceptual model of land information hinges on a complex spatio-temporal object model for defining not only collections of land parcel objects but also distributions of them within a four domain framework.