> Another problem with having to define prefixes upfront is that it makes > streaming production of output really hard -- if you don't know ahead of > time which namespaces you'll need you will be forced to include *all* of > them (whatever "all" means here) in the header.
That is true. It's not a problem I've had with RDFa per se, but in programmatically producing Atom, where the feed's <updated> date is required to come before the <entry> elements are listed. But the feed <updated> date is calculated by taking the most recent of the entry <updated> dates, so after writing the entries, I need to go *back* and fix the feed <updated> date. I wouldn't suggest creating a situation where similar annoyances will occur with RDFa. This is a strong argument against requiring CURIE prefixes to be declared in the <head> - the ability to declare them close to where they are used is very useful. -Toby
