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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: Parser Behaviour (serious)
 At 09:16 AM 4/3/00 -0700, Tim Bray wrote: >At 08:48 AM 4/3/00 +0100, Peter Murray-Rust wrote: >>So my summary is: >> - The experts (on this list) cannot agree precisely what a parser >>should >>and should'nt do with various combinations. these include: > >It is not clear that rules could ever be written. If this is true it spells the death of interoperability for information components such as MathML, SVG and CML (chemical markup language). What Tim is saying is that XML was designed to allow flexibility in the "application" - the software that processes the XML document. The receiver may wish to do this or that with it. I am sure this is perfectly reasonable for a large class of documents. It is clear that e-business is going to build islands of local operability - i.e. the same document will behave differently between in different environments (and may not even be processable in some). However I and many others are primarily concerned with the document itself and not its processing. The SVG example highlights this. SVG has the opportunity to revolutionise 2-D graphics ***if it is seamless at either end***. Alice sends Bob an SVG document and she has no knowledge of what software Bob is going to use ***and couldn't and shouldn't care***. She is sending him a graphics file whose *effective content* must be identical whatever the applications used. Otherwise SVG is already dead and IMO XML as well. In chemistry precision matters. Chemistry is used by a wide range of disciplines, many of whom have never used XML (yet, though henry and I are working on it). It is no good telling them: " make sure your parsers has access to the PUBID in a catalog so the external DTD is processed and the external entities are expanded". They will reach for their FORTRAN compiler. It matters very much. I and Henry are persuading may people to use CML as *part* of their content. Examples are publishers, patents, safety, health, materials, pharmaceutical, etc. etc. It is *absolutely essential* that everyone interprets the chemistry in the same way. Otherwise people could die. Example: "This product should be used for external use only. Ingredients: &organophoshate; &mercuricChloride; Always read the label: &seriousHealthWarning; &keepAwayFromChildren; This is not made up - I demonstrate this sort of thing when I promote XML. I (naturally) expect the external parsed entities to be included (or at least some serious error telling me the parser was lazy). There must be a relatively small finite number of combinations of parser behaviour. What I suggest we tackle is: - an *exhaustive examination* of all parser behaviours consistent with the XML1.0 spec - a clear tabulation and labelling of these - the requirement that a parser announce which of these behaviours it supports - the ability to select this behaviour - a means for the author of a document to communicate which of these behaviours she expects the receiver to use in their parser. I cannot believe this is impossible. If we don't tackle it MathML, SVG and CML are in the category of "this document can only be read with software X on browser Y on platform Z". Sounds familiar? BTW I use xp, Xerces and AElfred. I am finding great difficulty in finding command-line switches or other devices to influence their behaviour here. Could someone list for me how to change their behaviour on PUBIDs and SYSIDs in <!DOCTYPE foo PUBLIC "-//some possibly resolvable FPI" "http://some.internet.place"> Is it the same problem in <!DOCTYPE foo SYSTEM "http://some.internet.place"> Friends, this is too serious to ignore. We decided after a years' debate that we had to have an API for parsers (SAX). I think we know deep down we have to something here. It may be a document, it may be a piece of software. The response to SAX was so exciting and encouraging - everyone took it on board. I am absolutely sure that all parser writers want their parsers to be interoperable. The following expresses my desire: <!DOCTYPE molecule SYSTEM "http://www.xml-cml.org/DTD/v10"> <?xdev externalEntityExpansion="mandatory" DTDResolution="optional"?> <molecule name="raniditine bismuth citrate"> &ranitidine; &bismuth; &citrate; </molecule> <!-- I am not advertising - I happen to have worked on ranitidine --> P. *************************************************************************** This is xml-dev, the mailing list for XML developers. To unsubscribe, mailto:majordomo@x...&BODY=unsubscribe%20xml-dev List archives are available at http://xml.org/archives/xml-dev/ *************************************************************************** 
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