Donald Bren School of Information and Computer Sciences

We are in the midst of a paradigm shift toward component-oriented software development, and significant progress has been made in understanding and harnessing this new paradigm. Somewhat strangely then, the new paradigm does not currently extend all the way down to how the components themselves are constructed. While we have composition architectures and languages that describe how systems are put together out of such atomic program parts, the parts themselves are still constructed based on a previous paradigm, object-oriented programming. We argue that this represents a mismatch that is holding back compositional software design: many of the assumptions that underly object-oriented systems simply do not apply in the open and dynamic contexts of component software environments. What, then, would a programming language look like that supported component-oriented programming at the smallest granularity? Our project to develop such a language, Lagoona, tries to provide an answer to this question. This paper motivates the new key concepts behind Lagoona and briefly describes their realization (using Lagoona itself as the implementation language) in the context of Microsoft's .NET environment.