A Form-based Metamodel for Software Composition

In recent years considerable progress has been made to facilitate the specification and implementation of software components. However, it is far less clear what kind of language support is needed to enable a flexible and reliable software composition approach. Object-oriented programming languages seem to already offer some reasonable support for component-based programming (e.g., encapsulation of state and behavior, inheritance, late binding). Unfortunately, these languages typically provide only a fixed and restricted set of mechanisms for constructing and composing compositional abstractions. In this article, we will present a generic meta-level framework for modeling both objectand component-oriented programming abstractions. In this framework, various features, which are typically merged in traditional object-oriented programming languages, are all replaced by a single concept: the composition of forms. Forms are first-class, immutable, extensible records that allow for the specification of compositional abstractions in a language-neutral and robust way. Thus, using the meta-level framework, we can define a compositional model that provides the means both to bridge between different object models and to incorporate existing software artifacts into a unified composition system.