Converging CSP specifications and C++ programming via selective formalism

Abstract

CSP (communicating sequential processes) is a useful algebraic notation for creating a hierarchical behavioral specification for concurrent systems, due to its formal interprocess synchronization and communication semantics. CSP specifications are amenable to simulation and formal verification by model-checking tools. A translator has been created to synthesize C++ code from CSP for execution with an object-oriented framework called CSP++, thereby making CSP specifications directly executable. To overcome the drawback that CSP is neither a full-featured nor popular programming language, an approach called "selective formalism" allows the use of CSP to be limited to specifying the control portion of a system, while the rest of its functionality is supplied in the form of C++ modules. These are activated through association with abstract events in the CSP specification. This is a new means of bringing convergence between a formal method and a popular programming language. It is believed that this methodology can be extended to hardware/software codesign for embedded systems.

CSP as a Coordination Language

“…CSP++ [5], is a framework realizing CSP concurrency on top of POSIX threads for C++. The framework defines a whole development life-cycle starting with a CSP M specification being refined down to a CSP implementation model.…”

“…CSP++ [5] and JCSP [18] offer CSP-like channels as inter-thread communication facilities but realize only a limited set of CSP operators. The feature that distinguishes our approach from CSP-based software libraries is that events are not interpreted as communications over a typed channel but as abstractions of arbitrary actions.…”

The pilot approach to cluster programming in C

“…CSP4MPI [7] also aimed to help programmers avoid communication-related errors by introducing an abstraction layer over MPI. This approach was inspired by the CSP++ [8] software synthesis tool, which generates C++ from a formal CSP specification. However, CSP4MPI requires some user understanding of CSP, and feedback from SHARCNET staff responsible for new user training judged this impractical for the targeted user community.…”

A Formal CSP Framework for Message-Passing HPC Programming

“…In either case, the CSP-specified code constitutes a control backbone that invokes user-coded functions which carry out the desired calculations. This arrangement-mixing a formally-specified control structure with non-formal program code-is called selective formalism, and is key to our approach [6].…”