We study the typechecking problem for XML (eXtensible Markup Language) transformers: given an XML transformation program and a DTD for the input XML documents, check whether every result of the program conforms to a specified output DTD. We model XML transformers using a novel device called a k-pebble transducer, that can express most queries without data-value joins in XML-QL, XSLT, and other XML query languages. Types are modeled by regular tree languages, a robust extension of DTDs. The main result of the paper is that typechecking for k-pebble transducers is decidable. Consequently, typechecking can be performed for a broad range of XML transformation languages, including XML-QL and a fragment of XSLT. r 2003 Published by Elsevier Science (USA).
REF have studied a typechecking problem for their general framework called k-pebble Tree transducers, which can capture a wide range of query languages for XML.
Typechecking for XML transformers
J. Comput. Syst. Sci.
J. Comput. Syst. Sci.
Computer Science