SUMMARY Rendezvous‐based synchronization of concurrent autonomous entities is typically described in centric form distributed among the entities. An alternative associative form is also rendezvous‐based but shared between entities. This abstraction from collaboration is a descriptive unit and makes synchronization of entities simple and implicit. Copyright © 2011 John Wiley & Sons, Ltd.

The notion of associations as abstractions over collaborations is motivated and explored. This kind of association is seen as first class a concept at both modeling and programming level. Associations are seen as concepts/phenomena and possess properties. Properties of associations are characterized. A general event-based information sending and receiving mechanism is investigated as an example of a concrete form of property at the programming level.

Patterns are investigated in relation to the development of applications and frameworks in the context of analysis, design, and implementation. The results are based on a framework for virtual machines. Different pattern characteristics are identified in the analysis, design, and implementation of applications and frameworks.

When we apply the mechanisms of an object-oriented language, we form concrete architectures over some domain. Over time, we identify recurring patterns and transform the concrete architectures into more general architectural abstractions. Such abstractions are then used in combination with the language mechanisms to form other kinds of concrete architectures in diagrams and programs: we apply a combination of language mechanisms and architectural abstractions in the modeling and programming process. Our knowledge concerning the needs and possibilities in the modeling process, especially those captured in the architectural abstractions, enables us to invent new language mechanisms, typically abstraction mechanisms. Such abstraction mechanisms replace several architectural abstractions because of the generality of the mechanisms, and because of their integration with other mechanisms of the language: we invent abstraction mechanisms to replace architectural abstractions. "Software architecture" is the different styles and manners of building software in terms of the choice and combination of language mechanisms and architectural abstractions. The mutual influence between object-oriented language mechanisms and architectural abstractions is the basis for the further development both of languages and of software architecture.

Objects model phenomena and a phenomenon is usually a component. Information characterizing a component is encapsulated and accessible only by its methods. The relations between components are modeled explicitly by means of associations or references. A relation is also a phenomenon and objects can model this type of phenomena too. Components are usually related conceptually in diverse and subtle ways: Some relations are implicitly given and some are local to other more basic relations. Such kinds of relations are important for understanding the organization and cooperation of objects and may be supported in object-oriented analysis, design, and programming: An implicit association describes a relation between an object and objects local to this enclosing object, and a complex association describes an explicit relation between local objects in different enclosing objects. Such associations are described by classes and the objects have the usual properties including methods and attributes.

The BETA programming language is developed as part of the BETA project. The purpose of this project is to develop concepts, constructs and tools in the field of programming and programming languages. BETA has been developed from 1975 on and the various stages of the language are documented in [BETA a].

Abstract The possibility of supporting high level languages through intermediate languages to be used for direct interpretation and as intermediate forms in compilers is investigated. An accomplished project in the construction of an interpreter and a code generator using one common intermediate form is evaluated. The subject is analysed in general, and a proposal for an improved design scheme is given.