Prolog
Prolog, short for Programming in Logic, is a declarative programming language created by Alain Colmerauer and Robert Kowalski in 1972. It is primarily used in artificial intelligence, computational linguistics, expert systems, and symbolic reasoning.
XQuery
XQuery, short for XML Query Language, is a functional, declarative language designed to query, transform, and construct XML data. It is widely used in web services, document databases, content management systems, and enterprise integration pipelines where XML is a primary data format.