[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Comparable considered necessary
Joe English writes: > > The lack of clarity - heck, the outright refusal to acknowledge the > > question - about how to get from an identifier to a resource or back > > again - is the nails in the coffin. > > I disagree; refusing to acknowledge the question is the > only sensible thing to do. Asking "Do these two URIs identify > the same resource?" is like asking "are the chair in my living > room and the chair in my dining room both shadows of the > same Platonic Chair?" Better to unask the question; you > can't reliably get a useful answer. > > "Are X and Y the same URI?" is answerable. "Do X and Y identify > the same resource?" is not. That may be sensible given the difficulty of answering the question, but it also bars the kind of equivalence that makes naming schemes like DNS more predictable. As you pointed out: > according to DNS, > 'monasticxml.org', 'www.monasticxml.org', and '66.45.6.211' > are _also_ equivalent (at least today). That naming system provides a set of rules for working with named resources without spinning off into unanswerable signifier/signified questions. URIs unfortunately do not. I'm aware that a single name can point to multiple, context-sensitive, non-reversible, or changing answers, but the underlying principle is that it resolves to an answer consistently - heck, even an answer with metadata! > The only sensible thing to do is to treat all three of > these as distinct URIs. One _could_ argue that since > the 'http' scheme uses a server-based naming authority, > and since hostnames are case-insensitive according to DNS, > that the latter two should be considered equal. URI schemes all apparently have different rules for equivalence (if they even stoop to define one), and the move to IRIs is going to make that even more complicated by throwing in escaping. Do different escaping choices result in different URIs? -- Simon St.Laurent Ring around the content, a pocket full of brackets Errors, errors, all fall down! http://simonstl.com
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