The rendezvous constraint maintenance system

Abstract

The Rendezvousml language and architecture are designed to build computer-supported cooperative work applications that support simultaneous work at a distance. The language includes a feature-rich constraint maintenance system. The features in the constraint system were selected based, on feedback from user-interface developers using earlier versions of the Rendezvous language. Three important features in the constraint system are: indirectly referenced source and target variables, tolerance of side-effects, and special handling of uninitialized variables to simplify initialization. Application requirements that motivate these features and implementation techniques are described. The Rendezvous constraint system is faster, on some benchmarks, than other constraint systems currently being used for interface construction.