Adding implicit invocation to languages: Three approaches

Implicit invocation based on event announcement is an increasingly impor-tant technique for integrating systems. However, the use of this technique has largely been conned to tool integration systems|in which tools exist as indepen-dent 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 benet 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 dierent languages, Ada, C++, and Common Lisp. The intent is to highlight the key design considerations that arise in extending such languages with implicit invocation.