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Re: [www-vrml] X3D and the Draconian Parse Rule
Len,
The XML Encoding spec
(http://www.web3d.org/x3d/specifications/ISO-IEC-19776-FCD-X3dEncodings/Part01/concepts.html#XMLEncoding)
says that "[r]ules for parsing and handling XML-encoded documents
are defined in
2.[XML]."
This reference is
Extensible Markup Language (XML) 1.0 Specification, editors Tim
Bray, Jean Paoli, C. M. Sperberg-McQueen, Eve Maler, second edition, W3C
Recommendation, World Wide Web Consortium (W3C), Cambridge Massachusetts,
6 October 2000.
http://www.w3.org/TR/REC-xml
The XML Recomendation document says that "A data object is an XML document if it is well-formed". (http://www.w3.org/TR/REC-xml/#sec-documents) So being well-formed is a requirement for an XML document which is a requirement for a X3D (XML encoded) document.
What a particular X3D application does with a non-well-formed file is dependent upon the application. It is entirely legal for a browser to terminate during parsing of the document. A non-well-formed file may indicate the presence of transmission errors. The browser may not be able to detect other transmission errors (e.g., those in a IFS node), so quitting on a syntax error is probably the best thing to do.
You probably don't want your X3D/XML editor to quit when it encounters the error. This may be your only reasonable means for repairing the file.
Xj3D is taking a real strict approach to quitting when it detects an error. This would apply to XML syntax (document structure) and X3D syntax (node structure). This process is not required (at least I couldn't find anything in the spec about it).
To (finally) answer your question, what a browser "should" do is based on what the browser builder determines what best position this browser in the market.
Leonard Daly
At 07:48 AM 9/10/04, Bullard, Claude L (Len) wrote:
Given that X3D has multiple encodings, that one
is XML and that XML parse rules are not prescribed
by X3D but by XML 1.n, what should a browser do if
the file it is processing isn't well-formed?
len
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+--------
| Leonard Daly <daly@realism.com>
| Internet Development http://realism.com/
| e3D News Technical Editor http://e3dNews.com/
| SIGGRAPH 2002&2003 X3D Course Organizer
| Member, Web3D Board of Directors
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