Meta-scripts as a mechanism for complex web services

The World-Wide Web is the ´killer application´ of the mid-1990´s, and as a result it serves as the market place for various services. This position document discusses the problem of creating complex Web services from simpler ones, under client control. For example, one might want an annotated forecast of a company´s stock price from three simple services, viz., stock price data, forecasting and annotation. We propose meta-scripts as a solution. A client accesses a meta-script, which contains procedures for accessing and composing simpler services. Meta-identifiers are used in the meta-script instead of static links. Developments in type-consistency mechanisms and various enabling services of the Web help in realization of the meta-script based approach. This model of service composition separates control from data manipulation, and gives this control to a client. As clients are empowered with the selection and coordination of service providers, this can lead to a free market for services.