GPSL: A Programming Language for Service Implementation

At present, there is a dichotomy of approaches to supporting web service implementation: extending mainstream programming languages with libraries and metadata notations vs. designing new languages. While the former approach has proven suitable for interconnecting services on a simple point-to-point fashion, it turns to be unsuitable for coding concurrent, multi-party, and interrelated interactions requiring extensive XML manipulation. As a result, various web service programming languages have been proposed, most notably (WS-)BPEL. However, these languages still do not meet the needs of highly concurrent and dynamic interactions due to their bias towards statically-bounded concurrency. In this paper we introduce a new web service programming language with a set of features designed to address this gap. We describe the implementations in this language of non-trivial scenarios of service interaction and contrast them to the corresponding BPEL implementations. We also define a formal semantics for the language by translation to the join calculus. A compiler for the language has been implemented based on this semantics.