Technology

Wednesday, 29 October – 13:30-15:00

Chair: John Vlissides, IBM T. J. Watson Research Center, ddd@oopsla.acm.org

XAspects: An Extensible System for Domain-Specific Aspect Languages

Macneil Shonle, Northeastern University, mshonle@ccs.neu.edu
Karl Lieberherr, Northeastern University, lieber@ccs.neu.edu
Ankit Shah, Northeastern University, ankit@ccs.neu.edu

Current general aspect-oriented programming solutions fall short of helping the problem of separation of concerns for several concern domains. Because of this limitation good solutions for these concern domains do not get used and the opportunity to benefit from separation of these concerns is missed. By using XAspects, a plug-in mechanism for domain-specific aspect languages, separation of concerns can be achieved at a level beyond what is possible for object-oriented programming languages. As a result, XAspects allows for certain domain-specific solutions to be used as easily as a new language feature.
Keywords: Aspect-oriented programming, — programming, language extensions, domain-specific languages.

The Power of Symmetry: Unifying Inheritance and Generative Programming

DeLesley Hutchins, MZA Associates Corporation, hutchins@mza.com

I present the Ohmu language, a unified object model which allows a number of "advanced" techniques such as aspects, mixin layers, parametric polymorphism, and generative components to be implemented cleanly using two basic concepts: block structure and inheritance. I argue that conventional ways of defining classes and objects have created artificial distinctions which limit their expressiveness. The Ohmu model unifies functions, classes, instances, templates, and even aspects into a single construct – the structure. Function calls, instantiation, aspect-weaving, and inheritance are likewise unified into a single operation – the structure transformation. This simplification eliminates the distinction between classes and instances, and between compile-time and run-time code. Instead of being compiled, programs are reduced using partial evaluation, in which the interpreter is invoked at compile-time. Within this architecture, standard OO inheritance becomes a natural vehicle for creating meta-programs and automatic code generators— the key to a number of recent domain-driven programming methodologies.

Domain Driven Web Development With WebJinn

Sergei Kojarski, Northeastern University, kojarski@ccs.neu.edu
David Lorenz, Northeastern University, lorenz@ccs.neu.edu

Web application development cuts across the HTTP protocol, the client-side presentation language (HTML, XML), the server-side technology (Servlets, JSP, ASP, PHP), and the underlying resource (files, database, information system). Consequently, web development concerns including functionality, presentation, control, and structure cross-cut, leading to tangled and scattered code that is hard to develop, maintain, and reuse. In this paper we analyze the cause, consequence, and remedy for this crosscutting. We distinguish between intra-crosscutting that results in code tangling and inter-crosscutting that results in code scattering. To resolve inter-crosscutting, we present a new web application development model named XP that introduces extension points as place-holders for structure-dependent code. We present another model named DDD that incorporates XP into the Model-View-Controller (MVC) model to resolve both intra- and inter-crosscutting. WebJinn is a novel domain-driven web development framework that implements the DDD model. WebJinn has been used to develop web applications at several web sites. Domain driven web development with WebJinn benefits from a significant improvement in code reuse, adaptability, and maintainability.