Visual threads: the benefits of multithreading in visual programming languages

After working with the CWave visual programming language, we discovered that many of our target domains required the ability to define parallel computations within a program. CWave has a strongly hierarchical model of computation, so it seemed like adding the ability to take a part of the hierarchy and execute it in parallel would provide a good way of solving the problem. This led us to the concept of the Visual Thread and its associated components. Effectively, the Visual Thread allows the programmer to specify a part of the hierarchy and execute that part in parallel with the rest of program. We have used this implementation in several domains and demonstrated that it allows easy mapping of real world problems into our language. It eliminates most of the complexities often associated with programming parallel applications. We have also used a first prototype of our code generation system to translate CWave into Promela which allows us to verify correctness properties of the programs.