Reactive Multimedia Documents in a Functional

This paper presents one solution to the reactivity problem. A functional program gives a high-level description of a system; indeed, functional programs are often though of as `executable speci cations'. Here we use a functional language Haskell, [HP99, Tho99], to provide the foundation for constructing a toolkit for multimedia description, building on the Fran system, [PEL97, EH97], for reactive animation. The approach is demonstrated here by the development of two case studies which embody dierent degrees of interactivity or reactivity. In the remainder of the introduction we survey the background to the problem and other approaches to its solution. We then examine the reasons why we have adopted a functional programming language for our approach, and we conclude by surveying the rest of the pape