Expressing Temporal Behavior Declaratively

The programming language Arctic specifies real-time behavior declaratively by using temporal control constructs and by indicating starting times and durations explicitly, much the way timing is specified in a cue sheet or a musical score. Values in Arctic are functions of time, which may be combined with various arithmetic and logical operators. Since Arctic is a single assignment language, the execution order is implied by data dependencies, simplifying synchronization problems for the programmer. Arctic supports behavioral abstraction, in which a single program module gives rise, through various transformations, to a class of behaviors. An implementation of Arctic is described, and experience with the declarative approach to real-time control is discussed.