- From: Sean B. Palmer <sean@mysterylights.com>
- Date: Thu, 11 Apr 2002 12:25:55 +0100
- To: "Giles Hogben" <giles.hogben@jrc.it>
- Cc: <www-rdf-interest@w3.org>
> I would like to see some practical examples of > what real world problems are caused by the two > points of view. I think that people like to avoid talking about the pratical side of this argument, simply because there aren't many practical examples going around. It's a weakness, and so people aren't willing to discuss it. But there are problems. In the Evaluation And Report Language [1], we're basically quite stumped as to what things are being evaluated. For example, we might have the following Webpage that talks about a tool:- http://example.org/myTool Now, when you make an evaluation about that page, if you don't know whether it represents a tool, or some documentation about that tool, then how can you be sure what someone is evaluating? They might start saying that "it" is very accessible, for example that it passes all of the Web Content Accessibility Guidelines (the W3C content accessibility rec.) - but what is passing that, is it the page, or the documentation within the tool itself? Of course, you might be able to guess from the test. If you say that something's wheels are all properly balanced, then you can be pretty sure that it's a car. So the domain of some tests are quite obvious, but we have to account for those times when the domain is not obvious, and when the thing that the URI represents is unambigous. Note that Al Gilman has talked in more detail about the test domain idea [2]. Now, I've already bored people with EARL's "fix" for the problem (adding a layer of indirection). We could remove the indirection if we could know for certain that HTTP URIs identify "documents", since we could be fairly sure that the URI above represents some online documentation about the tool, and not the tool itself. If, however, the range of HTTP can be anything, then we're simply not sure. In that case, we have to go back to one of:- * Using the indirection predicates * Using the test case domain idea * Possibly looking at the headers for Resource-Type headers:- http://www.ietf.org/internet-drafts/draft-palmer-resrep-type-00 http://infomesh.net/2002/draft-palmer-resrep-type.txt So that's one potential way in which the range-of-HTTP issue affects users. In fact, there are a few more issues that are raised by the slightly larger hash vs. slash discussion. Here are some that I've been able to find:- Aaron Swartz: [[[ I want to create an HTTP proxy which I can host. Users who use this as their main HTTP proxy will see an RDF-annotated view of the Web, by typing URIs into their browser like normal. However, they'll get back a pretty version of all RDF assertions using that URI as its subject. Unfortunately, since RDF allows fragments as subjects there's no way for them to specify a fragment in their query, since the Web browser doesn't send it along (by design according to TimBL, see previous message). Thus they're not able to access all that information without big kludges in my software. ]]] - http://www.w3.org/2002/02/mid/B891F4F4.20BF5%25me@aaronsw.com Sean B. Palmer: [[[ Many people believe that fragments must be persistent; in the case of XPointer, that means that your XML document had better not change one iota. So, if you want to use XPointer, you have to do so on a resource that has a single fixed XML representation. That's absurd. ]]] - http://www.w3.org/2002/02/mid/009101c1e08a$3825e200$0c560150@localhost - http://lists.w3.org/Archives/Public/www-annotation/2002JanJun/0147 Tim Berners-Lee: [[[ From the outputter's point of view, when there is a hash, it takes the URI on the left and just looks it up in the prefix dictionary. When there is no hash, it doen't know where to make the break - you are allowed in principle to break half-way through a word. I *suppose* one could just have "/" as another option, but the optimum would be, I assumed, to search for the longest match. Which would be slower, but the serializer doen't need to be fast. ]]] - http://www.w3.org/2002/02/mid/000101c1756a$b49aedc0$eb13940a@CREST - http://lists.w3.org/Archives/Public/www-archive/2001Nov/0070 On the thread itself, I think that Miles Sabin is certainly onto something: this has never been a problem before because people haven't (and still don't) need to pin down the semantics of their hyperlinks. They can say "fred made a good quote on x", or they can say "this is a great new product: x", or they can go in between "here's a great new page about x". But now we're building a Semantic Web, we have to be stricter about what HTTP URIs identify, and that goes against how they've been used for ten years. Actually, it quite hillarious watching the argument, since both sides are trying to impose views against the general intuition of the majority of Web users. [1] http://www.w3.org/2001/03/earl/ [2] http://lists.w3.org/Archives/Public/w3c-wai-er-ig/2002Mar/0007 -- Kindest Regards, Sean B. Palmer @prefix : <http://purl.org/net/swn#> . :Sean :homepage <http://purl.org/net/sbp/> .
Received on Thursday, 11 April 2002 07:26:56 UTC