Cart
[Home] [By Thread] [By Date] [Recent Entries]
Hello. I understand that the XML 1.0 spec prohibits non-deterministic (or, ambiguous) content models (for compatibility, to be precise). Are all xml 1.0 compliant xml processing software required to reject DTDs with such content models? Ambiguous content models doesn't cause any problems when you construct a DFA via an NFA. I have heard that there is a way to construct DFAs directly from regexps without making an NFA, but that method can't handle non-deterministic regular expressions. If you choose that method to construct your DFA, you will surely benefit from the rule in XML 1.0 . But if you choose not, detecting non-deterministic content models become an extra job. I can see that parsers that allow non-deterministic content models may be harmful to the user. The user won't notice that his DTD may be rejected by other parsers. So there seems to be good reason for the XML 1.0 spec to prohibit parsers that accept non-deterministic content models. In that case the spec not only gives chance for a particular DFA constructing algorithm to be used, but effectively recommends the usage of the algorithm. --Hideo
|
