Fran (Functional Reactive Animation) is a collection of data types and functions for composing richly interactive, multimedia animations. The key ideas in Fran are its notions of behaviors and events. Behaviors are time-varying, reactive values, while events are sets of arbitrarily complex conditions, carrying possibly rich information. Most traditional values can be treated as behaviors, and when images are thus treated, they become animations. Although these notions are captured as data types rather than a programming language, we provide them with a denotational semantics, including a proper treatment of real time, to guide reasoning and implementation. A method to e#ectively and efficiently perform event detection using interval analysis is also described, which relies on the partial information structure on the domain of event times. Fran has been implemented in Hugs, yielding surprisingly good performance for an interpreter-based system. Several examples are given, including the ability to describe physical phenomena involving gravity, springs, velocity, acceleration, etc. using ordinary di#erential equations.

. We present our experiences using a purely functional language, Haskell, in what has been traditionally the realm of low-level languages: robot control. Frob (Functional Robotics) is a domain-specific language embedded in Haskell for robot control. Frob is based on Functional Reactive Programming (FRP), as initially developed for Fran, a language of reactive animations. Frob presents the interaction between a robot and its stimuli, both onboard sensors and messages from other agents, in a purely functional manner. This serves as a basis for composable high level abstractions supporting complex control regimens in a concise and reusable manner. 1 Introduction Robotics is a an excellent problem domain to demonstrate the power and flexibility of declarative programming languages. Among the more interesting problem areas in this domain are control systems, constraint solving, reactive programming, sensor fusion, and real-time control. We have developed Frob (for Functional Robotics) as ...

We present in this paper a simple, device-independent model for describing two-dimensional graphics using a functional language. Graphical scenes, or pictures, are represented as values that functions can manipulate and inspect to create new values. Complete pictures are constructed by repeatedly composing such picture values together using picture combinators. A novel aspect of the model presented is its use of structured translation to abstractly express the geometric composition of arbitrary pictures. The structured graphics model presented has been implemented in Haskell, and we also give an overview of a general rendering framework for traversing a picture value. Applications of this renderer include both output to various graphical systems, testing for picking or selection of a picture and the computation of the bounding box of an arbitrary picture. The graphics model forms the basis for all graphical output in a user interface framework being developed in Haskell. 1 Introductio...

this paper, we describe a library that provides basic types and functions to produce graphical documents in ML. This library is implemented on top of CAML [9] and CAML Light [8] in a functional style [7].