S+Net: extending functional coordination with extra-functional semantics

Abstract

This technical report introduces S + Net, a compositional coordination language for streaming networks with extra-functional semantics. Compositionality simplifies the specification of complex parallel and distributed applications; extra-functional semantics allow the application designer to reason about and control resource usage, performance and fault handling.The key feature of S + Net is that functional and extra-functional semantics are defined orthogonally from each other. S + Net can be seen as a simultaneous simplification and extension of the existing coordination language S-Net, that gives control of extra-functional behavior to the S-Net programmer. S + Net can also be seen as a transitional research step between S-Net and AstraKahn, another coordination language currently being designed at the University of Hertfordshire. In contrast with AstraKahn which constitutes a re-design from the ground up, S + Net preserves the basic operational semantics of S-Net and thus provides an incremental introduction of extra-functional control in an existing language.