Learn More
A language model is presented for the specification of User Interface Management Systems. The model, called the Abstract Interaction Tool (AIT) model, offers a tree-like hierarchy of interaction objects. Each object represents a subtree and can be considered as an abstract input device containing a syntax-like specification of the required input pattern.(More)
PROCOL is a simple concurrent object-oriented language supporting a distributed, incremental and dynamic object environment. Its communication is based on unidirectional messages. Objects are only bound during actual message transfer and not during the processing of the message. This short duration object binding promotes parallelism. The communication(More)
A <i>constraint</i> is a numeric or geometric relationship between objects. Constraints have a declarative nature and are a natural way for describing relationships between objects. Combining constraint systems and object-oriented programming (OOP) appears hard. All existing systems implicitly compromise the encapsulation principle of OOP. Also, the(More)
Input Input tools, originally introduced as a language model for interactive systems and based on high-level, input-driven objects, have been developed into a model for communicating parallel processes, called the input tool process model (ITP). In this model every process contains an input rule, comparable to the right-hand side of a production rule. This(More)
GPGS is a subroutine package offering powerful and versatile support for passive and interactive vector graphics, for time-sharing, batch, and stand-alone minicomputer systems. The package is computer, language, and operating system, as well as display device independent. Its key purpose is to allow for transportabiliit of programs and programmers by(More)