A high level language extension for creating and controlling dynamic pictures

Abstract

DALI (Display Algorithm Language Interpreter) is a special purpose high level programming language extension for the creation and control of dynamic pictures which exhibit complex static and dynamic interactions among their elements. DALI allows complex organizations of interpolated (“smooth”) change, discrete (“sudden”) change, and change to the structure of a picture to be generated in a modular way, in the sense that picture elements determine their own behavior and hence manner of change in a local manner. DALI pictures are composed of elements called picture modules . These are analogous to processes or procedural activations, and contain arbitrary event-driven procedures called daemons . Daemons, which are user-written, run under the control of scheduling rules based on the functional dependence of daemons on one another. These rules result in smooth inter-daemon (process) communication and cooperation with no implicit or explicit reference to semaphores or other synchronization primitives.