The DejaVu framework has a number of innovative features. First of all, we propose to employ inferential links as a means to traverse information stored in documents. Inferential links allow navigation on the basis of contextual knowledge. Such inferential links may be defined declaratively, in a rule-based way. The support for these links is provided by what we consider another innovative feature of our framework, a software platform that combines a low-level system implementation language (Active C++) and a high level logic-based distributed language DLP in what we call 'linguistic symbiosis'. An essential part of the (multi-lingual) environment is the hush (hyper utility shell) library based on Tcl/Tk, which enables the programmer to integrate (Tcl) script-based applications with C++ and DLP. To enable both the user and the developer of a hypermedia application to employ a script-like language to control the system, the framework provides an extendible hypermedia command language that offers the functionality needed to develop and tailor the user interface and contents of hypermedia systems. One of our research goals is to arrive at a declarative specification formalism that provides for both a high-level definition of the functionality of an application as well as support for the verification of invariance and consistency assertions. As part of the project we will develop some hypermedia applications to establish the validity of our approach. Further we intend to undertake a number of theoretical studies addressing the foundational and semantic issues involved.
Keywords: hypermedia systems, object oriented programming, visual languages, distributed logic programming, intelligent information systems, inferential links, rule-based information processing, declarative specifications, hypermedia command languages, meta programming

Hush Online Technology hush@cs.vu.nl 09/10/98