A method for parsing a document in an Extensible Markup Language (XML) format includes identifying data via the XML format, defining a tag set including a plurality of tags, defining a tokenizer that produces one token at a time, parsing the XML document via a parser, validating the XML document via a validation engine, the validation engine driving the tokenizer, the validating being an integral part of the parsing, and permitting the validation engine to be written in a recursive-descent code-driven manner.