Seminář: Grammar vs. Rules: Diagnostics in XML Document Validation, Semantic Annotation and Linking of Competitive Intelligence Reports for Business Clusters

Regular grammars has been used over decades for different formal language validation tasks because of their relative easiness of expression but more important because of their low computing expenses. Validation using regular grammars is commonly used also for XML document validation. In this case human understandable grammar definitions are converted into regular expressions which are evaluated against the input document. This approach is fast, straightforward but it lacks good diagnostics. It is hard for the validator engine to track grammar errors back to the information domain and provide some useful error messages understandable for the author. An alternative approach tends to be rule-based validation which is closely related to the modelled information domain. Rule-based approach gives very good diagnostics but it is more complicated to express simple parent-child relationships as in grammar-based languages. An interesting way how to gain advantages of both approaches is to support conversion from grammar-based schemes into rule-based schemes.

Experience from the research&educational project undertaken jointly with Tovek, s.r.o., will be discussed.