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Lars Marius Garshol wrote: > > * Vilya Harvey > | > | Just a thought: why not take a leaf out of the DOM's book and write > | the canonical version of the SAX interfaces in a language-neutral > | format like IDL? > > This may sound like a good idea, but it has its drawbacks in that one > is immediately forced into a lowest common denominator design where it > is impossible to make use of the features that really make each > language what they are. Ray Whitmer basically said what I wanted to say in his response to your post (thanks Ray!) so I won't repeat that; just consider me in agreement with the points he made. :-) > Also, IDL does not have convenient ways of mapping to C++ streams, > Java InputStream, Python dictionary-like objects and file-like objects > etc etc In theory though, you would simply define the functionality you required from a stream (to use your example) in an interface then make use of the appropriate "native" stream class in your implementation. That's not terribly inconvenient, and it needn't be inefficient either in a reasonable implementation. > Another problem is that exceptions are first-class objects in SAX > (which is exploited by the Java and Python mappings), but not in IDL. The only problem I see is that IDL doesn't allow exceptions to have inheritance. That would mean some slight changes to the API (although the implementations could still inherit from one another), but nothing really serious. Other than that, IDL only allows exceptions to declare member data (no methods); I don't see that as a real limitation though, since I have yet to see a *useful* example of an exception object with any methods other than getters/setters (which IDL member data gets mapped to) and printStackTrace(). > Nor are language naming conventions respected. (startElement should > really be startElement (in Java), start_element (in C++, Python, IDL) > and start-element (in Common Lisp/Scheme) and there may even be more > variations. Not everyone using a particular language follows the same naming conventions anyway, so I really don't think that should be a factor. As an aside, I disagree with you about the C++ name: I think it should be startElement not start_element. :-) Also as an aside, I haven't seen any IDL to Lisp or Scheme converters - does such a tool exist? > As a general reference and statement of intent it might have some > value, but I really think translation should be done by humans. I agree with you about this. > The main advantage feature of IDL, cross-process and cross-language > interoperability, is not really all that valuable for SAX anyway. I would argue that since SAX appears to be intended as a cross-language API, the main advantage of IDL would be its language neutrality. It would mean that the API would not be developed with the capabilities of one particular language in mind, as has happened with SAX 1.0. Of course whether or not that would be a real advantage is debatable but it would help avoid situations such as we currently have, where several incompatible C++ bindings have sprung up. Surely that's a good thing? Vil. (Not speaking for my employer.) -- Vilya Harvey <vilya@n...> Wilkinson House Mob: +44 961 106 505 Computational Mathematics Group Jordan Hill Road Wk: +44 1865 511 245 NAG Limited Oxford UK OX2 8DR Fax: +44 1865 311 205 xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To unsubscribe, mailto:majordomo@i... the following message; unsubscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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