Hyperform: using extensibility to develop dynamic, open, and distributed hypertext systems

An approach to flexible hyperbase (hypertext database) support predicated on the notion of extensibility is presented. The extensible hypertext platform (Hyperform) implements basic hyperbase services that can be tailored to provide specialized hyperbase support. Hyperform is based on an internal computational engine that provides an objectoriented extension language which allows new data model objects and operations to be added at runtime. Hyperform has a number of built-in classes to provide basic hyperbase features such as concurrency control, notification control (events), access control, version control and search and query. Each of these classes can be specialized using multiple inheritance to form virtually any type of hyperbase support needed in next generation hypertext systems. This approach greatly reduces the effort required to provide high quality customized hyperbase support for distributed hypertext applications. Hyperform is implemented and operational in Unix environments. This paper describes the Hyperform approach, discusses its advantages and disadvantages, and gives examples of simulating the HAM and the Danish HyperBase in Hyperform. Hyperform is compared with related work from the HAM generation of hyperbase systems and the current status of the project is reviewed.