Hi Hiranya, > project proposal is available at http://wiki.apache. > org/general/HiranyaJayathilaka/gsoc2008/xerces-j-proposal and I > would highly appreciate if you could review this project proposal > and send me your feedback on it.
I took a quick look at your proposal and it looks great. There are only a couple of minor points that may be worth mentioning. The proposal mentions that after schema traversal is done and before the schema is used for validation, there needs to be a place to store all the Type Alternatives. I just want to point out that you may want to take into consideration Xerces' schema model API (XSModel; org.apache.xerces.xs) and make sure that when that API is updated to support schema 1.1, it would be straightforward to implement the updated interface using whatever representation you choose for Type Alternatives. You've also mentioned "... and store them in a format that they can be easily evaluated ...". This is really important. XPath2 is a huge language. Including a complete XPath2 implementation (parsing and evaluation) in Xerces2 is probably not feasible. The spec defines a subset that every implementation must support (even that is bigger than what most people need in Type Alternatives). You may want to expand a little bit on your thoughts regarding how the XPaths should be stored. I don't think you need to go into that kind of detail in the proposal, but something to keep in mind. (It never hurts to plan ahead.) Other than that, again, the proposal looks really good! > Also I would like to know a few > more references to study the problem in hand before I get started. > I'm already looking into the relevant XML specifications. Unfortunately the Primer has not been updated to include materials for new schema 1.1 features, so the spec itself is probably your best friend to understand Type alternatives. You can also try to search the xmlschema-dev archive for something like "Conditional Type", e.g. http://www.w3.org/Search/Mail/Public/search?keywords=conditional+type&hdr-1-name=subject&hdr-1-query=&index-grp=Public__FULL&index-type=t&type-index=xmlschema-dev This gives you at least a few real-life scenarios where people could benefit from CTA. Or if you have any questions, either about CTA (or schema in general) or Xerces, flip me (or the Xerces list) a note and I'm sure there will be someone with the answer you need. :-) Thanks, Sandy Gao XML Technologies, IBM Canada Editor, W3C XML Schema WG Member, W3C SML WG (1-905) 413-3255 T/L 313-3255
