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Re: Relationship Taxonomy Questions



(Executive summary: You can skip this.)

Since silence from ERB members seems to be taken as indicating a
hidden agenda, I guess I'll have to state for the record that I agree
with almost everything that Eliot has said in his first couple of
messages in this thread.  (The odd phrasing at the end of that
sentence is due to the fact that my postings are sometimes taking
three or four hours to reach the list, so I don't know whether I will
be agreeing with whatever Eliot is saying by the time this is read.)

I will even go beyond that and venture a couple of opinions of my own,
some of which Eliot may agree with and some of which he may not.

1. Contra some statements which have been made by various people over
the last little while, it is not enough for XML to specify pure
syntax.  XML has to *interoperate*.  No shared semantics, no
interoperation.  The interesting, deep, and dangerous question is,
which semantics are the right ones to share?

2. I am quite convinced (and was before the ERB asked Eliot to start
this thread) that it is vital to make a strong distinction between

* Link structure or topology (one-to-one, one-to-many, etc.;
  independent, contextual, (possibly more))

* Linkend location/addressing

* Link meaning, which to me is effectively the same as relationship
  typing (owner-of, parent-of, see-ref-to, etc.)

* Link behavior, which can be divided into

  A. What the user sees:

     Presentation before link traversal
     Presentation during link traversal
     Presentation after link traversal

  B. What the system sees:

     State before link traversal
     State during link traversal
     State after link traversal

I personally have never seen anything specified in connection with a
link that could not be subsumed under some combination of these
categories; if anyone else can think of something, I sure would like
to know what it is.

2'. In particular, I think that it is of the utmost importance to
distinguish meaning (relationship typing) from behavior (which
includes presentation).  I think that the analogy between semantic
tagging vs. style information in SGML and relationship typing vs. link
behavior is an apt and powerful one.  So I am opposed to schemes that
collapse the distinction, for example by using traversal types such as
goto, etc., and prevent me from operating on meaning and presentation
as separate aspects of the document, just as I would be opposed to
collapsing the analogous distinction in SGML, and for essentially the
same reasons.

The preceding comments have added virtually nothing to this
discussion, but I hope that I have satisfactorily discharged my
obligation as a member of the ERB to put my position on record.

Jon


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