Extending functional languages with stateful computations

A new approach in which stateful computations can be performed within the framework of a functional programming language is presented. In most functional programming languages, programmers are unable to easily manipulate state-based computations which are not supported by functional languages. To solve this problem, the authors propose to extend the Sisal language with special user declared variables. This approach can greatly help users in writing programs, simplifying parallel compilation, and improving performance. Under this scheme, programmers are able to manipulate stateful computations. In the methodology, programmers are allowed to declare special variables, and the parallel threads can be identified according to the usage of special variables. When compared to "pure" functional languages, the extended Sisal has more expressive power due to the availability of stateful computations.