Synchronous Programming (Dagstuhl Seminar 13471)

Synchronous programming languages are programming languages with an abstract (logical) notion of time: The execution of such programs is divided into discrete reaction steps, and in each of these reactions steps, the program reads new inputs and reacts by computing corresponding outputs of the considered reaction step. The programs are called synchronous because all outputs are computed together in zero time within a step and because parallel components synchronize their reaction steps by the semantics of the languages. For this reason, the synchronous composition is deterministic, which is a great advantage concerning predictability, verification of system design, and embedded code generation. Starting with the definition of the classic synchronous languages Esterel, Lustre and Signal in the late 1980's, the research during the past 20 years was very fruitful and lead to new languages, compilation techniques, software and hardware architectures, as well as extensions, transformations, and interfaces to other models of computations, in particular to asynchronous and hybrid systems. This report is a summary of the Dagstuhl Seminar 13471 "Synchronous Programming", which took place during November 18-22, 2013, and which was the 20th edition of the yearly workshop of the synchronous programming community. The report contains the abstracts of the presentations given during the seminar in addition to the documents provided by the participants on the web pages of the seminar.