Adding Implicit Invocation to Languages: Three Aproaches

Implicit invocation based on event announcement is an increasingly important technique for integrating systems. However, the use of this technique has largely been confined to tool integration systems---in which tools exist as independent processes---and special-purpose languages---in which specialized forms of event broadcast are designed into the language from the start. This paper broadens the class of systems that can benefit from this approach by showing how to augment general-purpose programming languages with facilities for implicit invocation. We illustrate the approach in the context of three different languages, Ada, C++, and Common Lisp. The intent is to highlight the key design considerations that arise in extending such languages with implicit invocation.