A metalinguistic approach to process enactment extensibility

We present a model for developing rule based process servers with extensible syntax and semantics. New process enactment directives can be added to the syntax of the process modeling language, in which the process designer may specify specialized behavior for particular tasks or task segments. The process engine is peppered with callbacks to instance specific code in order to implement any new directives and to modify the default enactment behavior and the kind of assistance that the process centered environment provides to process participants. We realized our model in the Amber process server, and describe how we exploited Amber's extensibility to replace Oz's native process engine with Amber and to integrate the result with a mockup of TeamWare.