[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Namespace Comments (and dtd encoding)
David G. Durand wrote: > Well, it's not ugly, it allows re-use of prefixes without creating > conflicts. This is the point of a local scoping mechanism. A prefix is > essentially a variable, bound to a URI. the draft allows these variables to > be rebound within limite hierachically nested scopes (just like all modern > programming languages). These scopes are in one-to-one correspondence with > the element structure of a document, which for documents is the most > relevant hierarchy. > > It's true that DTDs cannot be aware of this right now, but it's also true > that local scoping is most useful incases where people want to add markup > to existing document intances (a key scenario for namespaces). It's also > true that after such dynamic markup, DTD validation is going to fail > anyway. As a member of the WG, I have been involved. I have agreed on colonization, and have always believed that colonization provides a good basis for the namespace extension. Now that we have local scoping and declaration by attributes, I start to wonder. (Skip the rest of this message if you do not want to hear.) Historically, we have always assumed that it should be possible to validate an XML document with namespaces with validating parsers of XML 1.0. This is not the case, any more. Since the same prefix can be bound to different namespaces, it is no longer possible to construct an equivalent XML 1.0 DTD from a collection of namespace-schema pairs. Then, what is the point of using prefixes? In my understanding, one reason that we chose colonization rather than reserved attributes is validation by XML 1.0 parsers. This reason no longer exists. (Note: The other reason was qualification of attributes.) Declaration of namespaces are inherited. But we also want to have inheritance of prefixes in the future. That is, we would like an element to inherit prefixes from superior elements. Thus, we will have complicated interaction of two types of inheritance. For example, it will become possible for an element to inherit a prefix and not to inherit a namespace dcl. One could argue that these two should always be in sync, but then what is the point of having the two? It would have been a lot simpler if we had introduced a reserved attribute for specifying the namespace of the element. Makoto Fuji Xerox Information Systems Tel: +81-44-812-7230 Fax: +81-44-812-7231 E-mail: murata@a... 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/ 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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