Environmental Science and Computer Programming

Generic programming is an effective methodology for developing reusable software libraries. Many programming languages provide generics and have features for describing interfaces, but none completely support the idioms used in generic programming. To address this need we developed the language G. The central feature of G is the concept, a mechanism for organizing constraints on generics that is inspired by

Multiple dispatch–the selection of a function to be invoked based on the dynamic type of two or more arguments–is a solution to several classical problems in object-oriented programming. Open multi-methods generalize multiple dispatch towards open-class extensions, which improve separation of concerns and provisions for retroactive design. We present the rationale, design, implementation, performance, programming guidelines, and experiences of working with a language feature, called open multi-methods, for C++. Our open multi-methods support both repeated and virtual inheritance. Our call resolution rules generalize both virtual function dispatch and overload resolution semantics. After using all information from argument types, these rules can resolve further ambiguities by using covariant return types. Care was taken to integrate open multi-methods with existing C++ language features and rules. We describe a model implementation and compare its performance and space requirements to existing open multi-method extensions and work-around techniques for C++. Compared to these techniques, our approach is simpler to use, catches more user mistakes, and resolves more ambiguities through link-time analysis, is comparable in memory usage, and runs significantly faster. In particular, the runtime cost of calling an open multi-method is constant and less than the cost of a double dispatch (two virtual function calls). Finally, we provide a sketch of a design for open multi-methods in the presence of dynamic loading and linking of libraries.

More and more aspects of concurrency and concurrent programming are becoming part of mainstream programming and software engineering, due to several factors such as the widespread availability of multi-core/parallel architectures and Internet-based systems. This leads to the extension of mainstream object-oriented programming languages and platforms–Java is a main example–with libraries providing fine-grained mechanisms and idioms to support concurrent programming, in

This paper brings together agent-oriented programming, organisation-oriented programming and environment-oriented programming, all of which are programming paradigms that emerged out of research in the area of multi-agent systems. In putting together a programming model and concrete platform called JaCaMo which integrates important results and technologies in all those research directions, we show in this paper that with the combined paradigm, that we prefer to call “multi-agent oriented programming” ...