Synchronous Automata for Synchronous Programming Languages

摘要

Synchronous programming [2] is available through several formally defined programming languages like Esterel[1], Lustre[3], Signal[5] and Argos[7}. Esterel is an imperative lan-guage while Lustre and Signal are declarative in style. Argos is similar to statecharts[4]. It is a graphical language which allows to program by constructing hierarchical automata. Although the languages are based on different programming paradigms, they all share the same computational model based on instanteneous broadcasting. Here are some examples without comment: While Argos (on the left) and Esterel (on the right) appear as somewhat similar, dataflow based programs, e.g. in Lustre, are dramatically different in style as demonstrated by the following trivial piece of code: node raising_edge (x:bool) return (y:bool); let false -> x and not pre(x) tel;