On Thursday, July 03, 2003 5:23 PM, Neil Graham <[EMAIL PROTECTED]> writes: > > How does this approach handle things like the schema unique particle > attribution or element declarations consistent constraints? > Clearly you > could parse schema documents simply using information from the > schema-for-schemas, but using that alone, surely it's not possible to > handle all conditions imposed on valid schemas by that spec.
Ah, Neil, you're a man in the trenches with Schema along with me! Briefly here, not to bore everybody with the details. The current schema for schema posted by w3c is _almost_ good enough to use without special treatment. But not perfectly. There are three issues we had with it: (1) The most serious is that the schema is not valid according to the particle valid (restriction) rule, so it simply doesn't compile [unless you use our -nopvr switch]. This is a known problem - let me dig out the email - link here: http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2002Feb/0027.html basically in the w3c the issue seems to have been left as "somebody just needs to fix the schema for schema" but the official posted s4s hasn't been updated to reflect this fact yet. So when we bootstrap with s4s we use a very-slightly-modified schema-for-schema that adjusts it, following Henry Thompson's suggestion in his proposal linked above. (2) The schema for schema redefines builtin types that are supposed to be built-in. Sort of like trying to define "int" in Java - it's not legal in a normal schema. So we basically special-case this situation in the compiler and ignore those definitions when compiling s4s. (3) S4s also hasn't been updated according to the errata that has to do with permitting whitespace in XPaths. So we removed the erroneous regular expressions from our bootstrapping S4S and deal validation of xpath syntax in our code. Other than that, things worked great. Relying on s4s has been a huge timesaver. Having schema validation and automated binding from an authoritative xsd file is really quite useful, just like us XML-heads have been telling people all along! David Bau XML Bean Architect --------------------------------------------------------------------- In case of troubles, e-mail: [EMAIL PROTECTED] To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
