RE: [xml-dev] 'is-a' Relationships in XML?

["G. Ken Holman" <gkholman@CraneSoftwrights.com>]

At 2010-05-03 20:44 +0000, stephengreenubl@gmail.com wrote:
>OK. Thanks for clarifying this. I agree to some extent, though a 
>spec usually takes it for granted that a child attribute applies to 
>the parent element, etc and doesn't necessarily spell this out or 
>that would make the spec too long. To have to state explicitly that 
>'date' is the date of the 'parent' document without letting it be 
>inferred that the date applies to the parent rather than a certain 
>child or sibling element seems to add too much to what the spec has 
>to spell out.

Not necessarily ... as Liam said, you are only constraining where to 
find the date information in the bigger picture.  It is up to 
extrinsic information to say what the date belongs to.  The 
containership provided by the use of syntax certainly helps as a 
guideline, but it isn't definitive.

>But if I accept in principle that semantics are added to XML in a 
>spec  or equivalent rather than relying on XSD and node names I 
>guess that makes a spec vital. It seems a little 'backward' if we 
>cannot formalise this using some XML technology though and have to 
>rely on human prose, doesn't it?

Not at all.  This was true also in SGML where it states the 
semantics/meanings are defined outside the DTD.  Markup has never 
defined semantics.

As for a formalism to associate known relationships between 
information components and other things or concepts (i.e. 
"semantics", the "meaning" of information), I've long thought that 
something like XML Topic Maps would be very useful in conveying that 
to users.  And it is conveyed in a machine-readable form.

But otherwise, absolutely it is up to prose to spell out semantics of 
the information that is captured in markup.  XML only constrains the 
syntax used to do the capturing.

I hope this helps.

. . . . . . . . . . . Ken

--
Principles of XSLT for XQuery Writers: San Francisco,CA 2010-05-03
XSLT/XQuery/UBL/Code List training: Trondheim,Norway 2010-06-02/11
Vote for your XML training:   http://www.CraneSoftwrights.com/x/i/
Crane Softwrights Ltd.          http://www.CraneSoftwrights.com/x/
G. Ken Holman                 mailto:gkholman@CraneSoftwrights.com
Male Cancer Awareness Nov'07  http://www.CraneSoftwrights.com/x/bc
Legal business disclaimers:  http://www.CraneSoftwrights.com/legal