The XL Web Service Language : Concepts and Implementation

The XL programming language has been build on two very simple premises. First, XML is the forthcoming language used to describe and communicate complex data. Second, services provided via the internet are complex but loosely coupled and use XML. Services are neither bound to a certain platform, computer, or application scenario. The interaction between service provider and consumer is based on availability and reliability of interface descriptions and the coherence to internet standards like HTTP and XML. The XL language provides the means to easily describe complex services based on the XML data model, the XML query language XQuery and an XML storage model. In the following, the ideas behind the XL language, the language itself, and the XL runtime engine used as a prototype will be described in detail. Furthermore, different statement processing concepts, different usage scenarios and the non-functional requirements of the runtime engine itself are discusse