Re: XML Base and "valid XML Resource Identifiers"

Regarding your example xml:base="{@xyz}", I don't see anything wrong
with it.  If the previous base URI was http://example.com/foo, The new
base URI will be http://example.com/%7B@foo%7D, which SHOULD (section
3.1) be returned by XML Base processors as http://example.com/{@foo}.

-- Richard