Streams, protocols, documents and fragments was: RE: Documents and Document Fragments (Was RE: XML Information Set Requirements, W3C Note 18-February-1999)

[James Tauber]

Jonathan Borden:
> I think this whole discussion is getting muddled because terminology of
>different domains is being interchanged.


Perhaps.

I am quite happy for people to use the term "document" or "logical document"
or "physical document" in a general sense. It is the term "XML document" I
am trying to be careful about. I'm not talking about streaming, or any
particular application, just trying to be clear on what is and what isn't an
"XML document".

My contention is merely that:

>> I don't believe you have an "XML document" until you serialise as
well-formed
>> XML text.

Consider:

    class Element {
        String gi;
        String content;

        Element(String gi, String content) {
            this.gi = gi;
            this.content = content;
        }

        String toXML() {
            return "<"+this.gi+">"+this.content+"</"+this.gi+">";
    }

Now if I say

    Element document = new Element("greetings","Hello!");

Then 'document' is *not* an XML document. It is a Java object.

If I say

    Element el = new Element("greetings","Hello!");
    String document = el.toXML();

Then 'document' *is* (potentially) an XML document (and also a Java object).

To put it crudely, it's gotta have the angled brackets to be XML.

That's my point. It's one I am quite willing to be corrected on, if someone
can show that the XML 1.0 REC allows for an XML document that doesn't begin
with the text "<" optionally preceded by whitespace.

[greetings {Hello!}] is a valid representation of the logical structure of
an XML document. It isn't an XML document.

><term>document</term> is defined as in the XML spec. documents are well
>formed. when a document fragment is isolated from its parent document, it
>becomes a standalone document.


In this thread I have tended to qualify "document", i.e. "XML document" to
(try to) avoid confusion with any discussion of documents in general.

You don't define document fragment anywhere. :-)

[...]
>So, the problem here is not one with XML, rather the protocol used to
>transmit documents, HTTP and SMTP send one MIME message per PDU,
>streaming protocols can be defined which transmit multiple documents.

I agree. This is not what I am arguing about.

James



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