Automata for XML - A survey

Since the arrival of XML as a data representation language, concepts from formal language theory like regular expressions, grammars and automata have been used for various purposes, e.g., as algorithm models for efficient evaluation of simple queries, as a proof tool, as a tool for static analysis and as an operational model with a clear semantics. Besides automata that read XML documents as strings, called document automata in this article, tree automata play an important role, as XML documents have a tree structure and for many applications it is possible to abstract away from text and data details and to model XML data by labeled trees.