Agile programming with executable models: an open-source, standards-based eclipse environment

Why can it be so hard to extract the "truth" from the code, especially on important big-picture, architectural issues in large systems? Models designed for human understanding can display these things much more clearly, but how do you keep the models in sync with the code? Well, suppose the model was the code -- then you could have the best of both worlds! This is, indeed, possible, as is demonstrated using a combination of standard UML graphical class modeling and standard Alf action language programming, all based on a common, standard executable semantic foundation, new capabilities implemented in the Eclipse Papyrus UML tool. The result is a step toward a next generation agile programming environment.