The SL synchronous language

Abstract

We present a new synchronous programming language named SL based on Esterel, in which h ypothesis about signal presences or absences are not allowed. Thus, one can decide that a signal was absent during one instant only at the end of this instant, and so reaction to this absence is delayed. Esterel \causality problems" are avoided at the price of replacing strong preemptions by weak ones. An operational semantics based on rewriting rules is given and an implementation is described which allows either to directly execute programs, or to produce automata.

A Semantic Theory of the Internet of Things

“…As already said, CaIT has some similarities with the synchronous languages of the Esterel family [4,6,3,1]. In this setting, computations proceed in phases called instants, which are quite similar to our time intervals.…”

“…Thus, time synchronisation relies on some clock synchronisation protocol for mobile wireless systems [36]. However, our notion of time interval is different from that adopted in synchronous languages [4,1,6] where the environment injects events at the start of instants and collect them at the end. In the synchronous approach, events happening during a time interval are not ordered while in our calculus we want to maintain the causality among actions, typical of process calculi.…”

Synchronous Programming

“…This is the most conservative solution as it suppresses the problem. This solution has been adopted in Lustre [10], SL [11], and several execution modes of discrete-time Simulink. 3 Rely on an arbitrary ordering of actions within a time step.…”

What Is in a Step: New Perspectives on a Classical Question

“…This interpretation has gained some importance in the synchronous programming community. Examples are Boussinot's Reactive-C [9], Boussinot and de Simone's synchronous reactive calculus SL [12], Mandel and Pouzet's functional reactive programming language ReactiveML [45], and Boussinot and Dabrowski's FunLoft [11] which is a globally asynchronous, locally synchronous model of multi-threading. The idea is also applied in logic programming, specifically in Saraswat, Jagadeesan and Gupta's language tcc for timed concurrent constraint programming [53].…”