While writing up the minutes for today's call it hit me that I goofed on the discussion of the relevance of OpenFormula to the W3C's work. For some crazy reason I mentioned XSLT as relevant. This is not really true.

The relevant connection would be to XPath, which has a "core function library", which could be supplemented:

http://www.w3.org/TR/xpath/#corelib

XForms, for example, keeps the basic syntax of XPath but supplements it with additional functions:

http://www.w3.org/TR/xforms/#expr-lib

OpenFormula (at least the function library) could be a another source of extension functions.

Regards,

-Rob