[sc34wg3] Questions on N0396: (16) locators

Murray Altheim sc34wg3@isotopicmaps.org
Thu, 24 Apr 2003 00:04:03 +0100

Lars Marius Garshol wrote:
> * Jan Algermissen
> | 
> | N0396 says in 3.1:
> | 
> | "A locator is a string that references one or more information resources"
> | 
> | The note at the end of 3.4.5 says:
> | 
> | "Locators which refer directly to subjects which are not information
> | resources must be used with caution. They should not be used in the
> | [subject addresses] property, as this is intended only for references
> | to information resources. Rather, they should be placed in the
> | [subject identifiers] property."
> | 
> | The two statements contradict each other.
> They do, though I would perhaps rather say that the note expands on
> the definition. It turns out that whether we want it or not there are
> URIs that do not reference information resources.
> | I strongly advice us NOT to try any 'fixups' towards
> | interoperability with RDF. I think that topic maps are far better of
> | if they stick to the idea that "a URI allways refers to the
> | information resource that (might) be returned by an HTTP GET. There
> | are no locators that refer to abstract concepts." Anything else is
> | introducing evil, IMHO.
> The trouble is that URIs were defined by the IETF and we can't change
> them. It's a fact of life that there are quite a few URI schemes that
> do not reference information resources and there's not a whole lot we
> can do about it. It's impossible to outlaw them in any meaningful way,
> and to pretend that the problem does not exist is the worst we can do.
> Note that there are many other kinds of URIs than just "http://" ones.
> We can't disallow ftp, nntp, gopher, news, mailto, ... URIs, nor the
> more dubious ones like urn:isbn:..., tdb:..., and so on.
> This is SAM issue locator-reference, BTW:
> <URL: http://www.ontopia.net/omnigator/models/topic_complete.jsp?tm=tm-standards.xtm&id=locator-reference >

Honestly, I haven't been following this discussion all that closely,
but it sounds very much like you're trying to solve all the world's
problems, which is a problem in itself. This is like trying to figure
out what to do with edge cases like URI references that are empty
strings. Yes, they exist. No, the SAM doesn't have to answer all of
the possible questions on all the existing muck that's been created
in the past ten or twenty years. Perhaps a horse blinder approach,
a tighter scope?

Dunno, it just seems like a Sisyphean task in front of you, and I
can't think of too many specs that attempt it. Put it another way,
within the W3C they've spent many *thousands* of hours arguing over
what URIs are and what they mean and what they taste like fried up
in butter. It's not worth the pain, really.


Murray Altheim                    http://kmi.open.ac.uk/people/murray/
Knowledge Media Institute
The Open University, Milton Keynes, Bucks, MK7 6AA, UK               .

                                                Moonlight slanting
                                                  through all the
                                                  bamboo forest...
                                                and nightingale song
                                                          -- Basho