Attributes with Intent (and namespaces)
James.Anderson at mecomnet.de
Fri Jul 3 15:50:38 BST 1998
please bear with me; maybe we're getting to something here...
MURATA Makoto wrote:
> I strongly disagree. The whole point of the namespace extension is to
> allow applications to tell which namespace a name belongs to. A qualified
> name is not an opaque object. Application programs should and will care
> the attached URI.
so far, as i've understood namespaces (wrt xml):
1. the NSDef will bind an URI literal. beyond that the value is of unspecified
form and content.
2. the prefix has a bearing on encoding and decoding only.
3. the universal name arises through the uniqueness of values in the relation
(NSDef.SystemLiteral X QName.LocalPart)
i presume everyone agrees up to here. ...
now, to the reasons the <EM>value</EM> of the uri does not matter to an application:
4. the purpose of the mechanism "articulating" the namespace is to control the
declarations made about a name. this is, among other things, the
schema-reuse goal in
5. the application's concern is that, given a universal name, it can determine the
declarations or effect the declared behaviour.
6. to accomplish this, the application will depend on functions of the form
(UniversalName) -> (Declaration + Behaviour)
7. there are no occasions when the application will need a function of the form
(URI) -> (Declaration + Behaviour)
8. functions of the forms
(URI X LocalPart) -> UniversalName or UniversalName -> (URI X LocalPart) or even
(URI X UniversalName ) -> UniversalName
are necessary for dom construction operations only.
(yes, this is not a w^3 conform dom, and yes i advocate that the
application use a dom)
9. functions of a form such as
(URI X LocalPart) -> (Declaration + Behaviour)
are unnecessary, since, at the application level, <EM>given a dom</EM>
operation of the
(URI X LocalPart) -> UniversalName
simply makes no sense. they whould be well constructing names which have no declarations.
in order words, "the uri does not matter to the application".
10. where the intent is to establish a relation between two universal names,
(see the forgoing discussion in this thread)
there may be a need for functions in domains such as
(URI X URI) -> ? or (UniversalName X UniversalName) -> ?
but the effects of these (and here i again cross the line to advocacy)
should be declared
at the decoding level, just as with operations using functions
(Prefix X URI) -> NSRegion
which declare namespace regions, .
given the exposition above, where do we diverge?
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