what is "completely different" [Re: RDF, Namespaces, and Versioning?]

David Megginson david at megginson.com
Wed Feb 10 19:35:42 GMT 1999


james anderson writes:

 > What is the concensus (?!) here on how one should interpret
 > "completely different" in the passage below?
 > 
 > David Megginson wrote:
 > > 
 > > In other words, ... I cannot use
 > > "{http://www.megginson.com/ns}result" in two different specs for two
 > > completely different purposes.

By 'use', I actually meant 'define', but James's question is still
worth tackling.

James asks about specific points like content models, attribute types,
etc. -- what is the proper use of a name defined in a namespace?  I'd
suggest that that's all dependent on the degree of specification.

As an example, consider the specification for elements named
{http://www.megginson.com/ns/foobar/}place.  Here's one possible
example:

  An element named {http://www.megginson.com/ns/foobar/}place shall
  always contain the name of a geographical location.

Since I've used the verb "contain", I think that I cannot put the name
in an attribute value (since attributes are not contained in an
element):

[WRONG] 
  <megg:place name="Ottawa"/>

However, I've said nothing about what the name should look like or how 
it should be structured, so all of the following should be conformant:

[OK] 
  <megg:place>Ottawa</megg:place>

[OK] 
  <megg:place>Ottawa, Ontario, Canada</megg:place>

[OK]
  <megg:place>The city of Ottawa</megg:place>

[OK] 
  <megg:place>
    <city>Ottawa</city>
    <province>Ontario</province>
    <country>Canada</country>
  </megg:place>

[OK] 
  <megg:place>
  Ottawa<br/>
  Region of Ottawa-Carleton<br/>
  Ontario<br/>
  Canada
  </megg:place>

[OK]
  <megg:place>
  <item>Ottawa</item>
  <item>Ontario</item>
  <item>Canada</item>
  </megg:place>

If I want something more specific, I have to give it in the definition 
(perhaps by supplying BNF or a content model, or even by specifying
the allowed structure of the character data).


All the best,


David

-- 
David Megginson                 david at megginson.com
           http://www.megginson.com/

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