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   Re: [xml-dev] Xml is _not_ self describing

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On Tue, 2002-01-15 at 17:24, Nicolas Lehuen wrote:
> Maybe the term of "self-describing" should be made more precise by
> specifying the intended audience and purpose of the self-description.
> The -ing for is tricky : "self-describing" seems to mean that the data by
> itself can reify its meaning.

While this may be technically correct, I think the point itself is
meaningless if not downright dull.

> - However, outside the bounds of very precise algorithms (validation), an
> XML document with an embedded DTD is not self-describing for computers in a
> more general processing context. Nothing tells the computer about how the
> data should be processed. The document has no control over its own fate. An
> invoice document is not describing how it should be processed by an
> accounting system. The information comes from elsewhere.

Of course the information comes from elsewhere.  Labels are meaningless
without someone/something/somewhere to interpret them.  This is hardly a
new phenomenon, nor does it negate the potential usefulness of those
labels to someone prepared to interpret them.

> The latest point means that the hype 'because XML is self-describing, it is
> the Lingua France of computer science, and your integration costs will drop'
> is pure bullshit. We know it for sure on this list, but explaining why needs
> a precise definition of what 'self-describing' means...

Bullshit it may be, but I don't think it has a damn thing to do with the
meaning of "self-describing".  XML has a substantial advantage over
other formats because of its deeply flexible labeled structures.  That
isn't magic - it's just useful stuff we can use in a wide variety of
different situations.

Does XML lower integration costs?  I believe it usually does, as
exchanging labeled structures is a generally good approach to
communications between dissimilar systems.  Does it make integration
costs vanish?  Of course not.  Reasonable expectations are more likely
to be rewarded.

Can we stop arguing about non-existent claims of magical goodness?  It's
almost as bad as limericks.

Simon St.Laurent
Ring around the content, a pocket full of brackets
Errors, errors, all fall down!


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