[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Another look at namespaces
-----Original Message----- From: David Megginson <david@m...> To: XML-DEV <xml-dev@i...> Cc: Tim Berners-Lee <timbl@w...> Date: Friday, September 17, 1999 3:23 PM Subject: Re: Another look at namespaces >Tim Berners-Lee writes: > > > That is not useful. I realize that the word "Namespace" (as the > > end result fo the discussions of modules or docuemnt types or > > vocabularies or...) may be an english word which does not convey > > this, but a a namespaces is a language: a set of names plus a set > > of syntactic constraints plus - to be useful - a meaning shared by > > writer and recipient. > >As (I think) Tim is arguing later in his message, a Namespace is a >component of a vocabulary: specifically, it's the mechanism that XML >documents use to represent (and disambiguate) the names that are part >of a vocabulary, but, as Rick argues, it's not the vocabulary itself. > >Since Paul Prescod mentioned Chomsky, I'll mention Saussure: like >written or spoken words, a namespace-qualified name is a pure <foreign >lang="fr">signifiant</foreign> without any <foreign >lang="fr">signifiée</foreign>. There is a signifiée, unless the namespace is useless. To design a namespace with no meaning is a possible excercise but as documents written in such a namespace would have no meaning. The namespaces spec doesn't tell you how to describe the meaning of a name. But that does *not* mean that it should have none. >For example, the signifier "{http://www.megginson.com/ns/}apt" can be >represented by Namespaces. The signified (say, "a valid ICAO airport >code") cannot be represented by Namespaces, but for now will probably >be represented in human-readable documentation and hard-coded in >applications. > >I guess that a machine-readable schema could constrain the element to >contain up to four alphanumeric characters, but who cares, really? > My >application still has to know somehow that it's an airport code and it >has to know what it wants to do with airport codes (sell you a ticket? >give you driving directions? tell you that the document contains a >match for the code you were looking for?). But once your application can do that with a http://www.megginson.com/ns#element-apt then an RDF assertion that http://www.blee.com/ns2 is-subset-of http://www.megginson.com/ns will allow your application to know automatically how to process airport codes in my vocabulary. I just declared mine to be a subset of yours. Or I might in a schema want to assert that http://www.blee.com/ns2#element-airportcode is-equivalent-to http://www.megginson.com/ns#element-apt >David Tim 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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