[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Web Resource Identity
Paul Prescod writes: > David Megginson wrote: > > > > But you cannot always take two references and determine if they do > > *not* refer to the same object -- that depends on the design. > > "Do these refer to the same object?" => Yes/No/Maybe > > I'm not familiar with a system like that. Can you give an example? You will often end up with two objects that represent conceptually the same thing but cannot be proven equivalent (two medicare records, for example); in fact, you may even have objects that share the same set of attributes but cannot be proven equivalent. There's also the case of lazy Java programmers who don't override java.lang.Object.equals() (that represents a significant percentage of existing Java code, I'd guess). > Obviously boolean logic is MUCH easier to work with than tri-nary > logic. No, in the case of URLs, it's still binary: "Are these known to refer to the same object?" => Yes/No And while a cononical URL is an easy extension to HTTP, the infrastructure to support it is another issue -- do I have to guarantee, for example, that a gzipped tar file of the same version of the Linux kernel source at two different mirrors return the same canonical URL? All the best, David -- David Megginson david@m... http://www.megginson.com/ xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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