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In my mind, choosing one schema over another is driven by the depth of validation I can express and execute with each. Can I validate with a regular expression? Can I express cross-field constraints? Is there a mini-language to do arbitrary computational tests? Can external validation and consistancy, including relational-style tuple existance be expressed in an abstract way? When we have actually used Schemas, these are the kinds of things that became apparent needs. It may be that some particular line delineates what should and should not be in a schema, but it is apparent that this will evolve. First is syntax and minor semantics, full semantic validation seems a logical path, but implies a lot potentially. There are multiple solutions, probably explored by committees in the past. "Baby steps. Baby steps. When you're ready." Now, is it additionally important to efficient load (somewhat) and 'execute' (definitely) a schema? Does it need to have a binary representation? Depends. Schemas can usually be cached, precomputed, and involve other efficiencies. You can think of situations where this doesn't hold. Still, it's nothing like the efficiency needs of the data itself. sdw Bullard, Claude L (Len) wrote: >I don't buy it. I buy that people are creating alternative >syntaxes, alternative applications (eg, RELAX NG which may >or may not have an 'unstoppable momentum' but has yet to >show up in an RFP so not in prime time yet). I don't buy >that these are easier to learn or read once one is comfortable >with XML. To me the ease of any one feature or the complexity of >any one language is quickly overcome by the network effect of >instances and tools shared widely. > >Is a binary characterization group a mandate to open up a >full up replacement or large scale revision of XML? I doubt >it. Syntax is NOT trivial. > >We've had simpler syntaxes before. We've had binaries before. >We've never had integration at this scale. We have to be very >conservative what of the various experiments in the wild are >adopted into the standards of a working system. > >len > > ... sdw -- swilliams@h... http://www.hpti.com Per: sdw@l... http://sdw.st Stephen D. Williams 703-724-0118W 703-995-0407Fax 20147-4622 AIM: sdw begin:vcard fn:Stephen Williams n:Williams;Stephen email;internet:sdw@l... tel;work:703-724-0118 tel;fax:703-995-0407 tel;pager:sdwpage@l... tel;home:703-729-5405 tel;cell:703-371-9362 x-mozilla-html:TRUE version:2.1 end:vcard
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