XL is a discondinued an XML programming language for implementing Web Services. It was created in 2001 by Daniela Florescu (XQRL Inc.), Andreas Grünhagen and Donald Kossmann (ETH Zürich). XL was based on the XML data model. It supported the W3C standards and used XQuery as a query language, SOAP to communicate with other web services and WSDL to specify the interfaces.
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XL (XML programming language) Wikipedia(Text) CC BY-SA