Cart
[Home] [By Thread] [By Date] [Recent Entries]
robin.berjon@e... (Robin Berjon) writes: >> I don't think that changes the argument about the value of generic >> linking at all. To put it bluntly, "one linking mechanism to rule >> them all" is ridiculous on its face. > >Blunt is fine, but this particular instance is tragically unhelpful. >Why is it ridiculous on its face, does it have a big red shiny nose or >something? Ah, "tragically unhelpful". I take it that means that we're getting close to the heart of the problem. WHY "ONE LINKING MECHANISM TO RULE THEM ALL" IS RIDICULOUS Broadly speaking, there are two ways to look at links. The first way abstracts the notion of "link" from a wide variety of practices. Any connection between two resources can be a link, whether the connection is annotation, a sign of traversal, an informational cross-reference, a key relationship in databases, or whatever else seems to be convenient at the time. The second way doesn't seek out "links" per se. Instead of a grand unified theory of links, it encourages people to connect information as they find convenient to the projects on which they work. Generalization can and will occur as people share information which uses links, but there's no notion that all of these things are necessarily the same. XML is in many ways an opportunity for the second way, because the enormous vocabulary flexibility it provides gives enormous room for experimentation. XLink took the first route. There's a general notion of a "link" containing resource identifiers, paths between them, and metadata. The role, arcrole, title (sort of), show, and actuate attributes let developers customize their own links from a single standard notion. Role and arcrole act as URI-based escape hatches (a favorite W3C approach) which are basically "say what you really mean here". In its early drafts, while XLink used this approach, it at least preserved some degree of vocabulary flexibility. As namespaces came into common use, XLink lost that flexibility as well, and now we have a situation where XLink is not merely a common model but a fixed syntax, and that URI escape hatch isn't enough to let people do the things they want with links. The HTML IMG and the HTML 2.0 "href everywhere" cases make that painfully obvious. Much of the opposition to XLink has come from its top-down imposition of a single way of looking at links. The many battles over show and actuate and whether they should even be in the spec, the fights over links as sets vs. links as traversal paths, and concerns about integrating this with existing vocabulary and practice all look to me like well-earned friction. XLink's thorough failure to make friends, even within the W3C reinforces my suspicion that its approach was simply bone-headed to start with. "There's more than one way to do it" seems especially important in linking, where even just the hypertext field of linking is marked by incredible diversity and a wide range of conflicting opinions. I'm not sure what gave the XLink working group the moxie to think that they could develop the one true way for linking XML documents or the W3C TAG the gall to expect the HTML WG to conform to that way, but I regard it as perhaps the saddest chapter of XML history. Perhaps some day we'll have enough experience to say that "this abstraction of linking is good enough to cover all cases and be used this way". Unfortunately, I don't think that specifying an abstraction and a syntax now gets us anywhere near that. Even if you really think there's a Platonic Form of linking out there, it's hard to claim that assembling a committee to develop an XML vocabulary is going to get anyone near there. If you think linking is a simple enough field to be modeled this way, I'm afraid I have to suggest that you haven't taken linking nearly seriously enough. Even in the simplest cases, though, I have a really hard time finding benefits to XLink that aren't outweighed by the costs of using it. Junk it. -- Simon St.Laurent Ring around the content, a pocket full of brackets Errors, errors, all fall down! http://simonstl.com -- http://monasticxml.org
|
