Summary: Synchronous Programming
Properties within a Reaction
Charles André* -- Robert de Simone**
* Laboratoire I3S, UMR 6070, Université de Nice/CNRS
06903 Sophia Antipolis Cedex, France
** INRIA Sophia Antipolis
06902 Sophia Antipolis Cedex, France
ABSTRACT. Complex reactive behaviours can be expressed by synchronous imperative formalisms
like ESTEREL or SYNCCHARTS. To make the best of these models and to avoid the pitfall of
"causality cycles", the user has to understand the underlying semantics, known as the "con-
structive semantics". The first part of this paper is an informal introduction to this semantics.
In the second part, this semantics is used to analyze "intra-instant properties" (partial order-
ing of simultaneous action executions). It appears that the compiler, which implements the
constructive semantics, can carry out such analyses. Our method is illustrated by a zFIFO
(0 fall-through time FIFO queue), which is a system envolving numerous simultaneous actions
whose execution order may be critical.