Towards a Type Theory of WS-CDL Based on Process Algebra

The language of choreography, WS-CDL, is a W3C candidate recommendation standard, which is an interactive description from global view but the language lacks formal semantics. WorkUnit in WS-CDL plays a crucial role because of reusable principle. In this paper, we propose process algebra for WS-CDL (PA4WS), which equips workunit. The semantics of PA4WS are presented based on structural operational semantics. Particularly, the notation of service channel and session channel are implemented in PA4WS. Moreover, we give the type theory of PA4WS and show the properties of the type theory, for example, the subject congruence and the subject reduction etc. Finally the benefits of PA4WS are ex-emplified by an e-business case and its descriptions of PA4WS.