W. Eliot Kimber wrote:
> But I think that what Aaron is really asking for is some sort of
> analyzer that can report whether or not there are any attributes with a
> declared type of "ID"--if not, then id() can never work. If so then id()
> might work.
Yes, I understood this. In particular, id() will never work
if there is no DTD, as in his original question. Unfortunately,
the XSLT spec leaves it to the processor whether to regard
this as an error or just work on.

But xsl:key() is fundamentally no different from "//*[@id='$name']"--it
still requires that you know, for a given input document, what the ID
and IDREF attributes are.

Id() requires you to know which attributes are IDREF too.
Ok, it will work with IDREFS which is painful without it.

I personally prefer to know under which name IDs are
sailing so that I can avoid doing silly stuff, like
reading the full DocBook DTD each time a 5kB XML file
is to be served just to get the ID attributes.