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Simon St.Laurent wrote:
> On my way back from XML 2001, I started thinking about the conference
> I'd just seen and how exactly I landed in XML. Wandering through a
> bunch of different loosely-connected ideas, I started thinking that XML
> and markup in general - including and perhaps especially SGML - simply
> doesn't fit well with a huge amount of what the rest of computing wants
> to believe.
> I'm sure this is obvious to some people but may be worth exploring in a
> little more detail for others.
> Labeled and hierarchically structured information seems very useful to
> XML folks, and it's pretty simple to work with as XML. Put those
> labeled hierarchies into another framework - say, objects or relational
> databases - and suddenly what was simple gets complicated very quickly.
I must say that nowadays when I hear "object oriented programming" and "XML"
in the same sentence I slightly cringe. The first instinct one has, coming
from an object oriented background, is to meld the two together. This was my
inclination when I was more new to XML (e.g. the XMOP project
http://www.openhealth.org/documents/XMOP.htm), but the more I have had time
to reflect on things, the less this interests me.
> XML seems to encourage a diversity of data structures (even within the
> same document) which don't echo the relative conformity of both object
> and relational structures.
right. limiting oneself, limits oneself.
> The notion that representation is as important as underlying structure,
> which XML's syntactic rules make fairly explicit, is deeply alien to the
> Platonic view of information that many programmers seem to share. The
> notion that lexical structure might be as important as the underlying
> information is one that even this community frequently has difficulty
> with, but it seems to be at the foundation of XML 1.0.
right again. objects tend to treat data as opaque, one tends to access data
_through_ an object, not directly as one might access XML.
> I'm not sure that any of this is new or unusual - most of it's probably
> obvious to a lot of people.
No, I would guess that most people, including many experienced people, have
much trouble distinguishing between objects and XML.
> Maybe I've been working in the XML trenches too long, but it seems like
> maybe it's time to say "XML is different from the rest of what you've
> been working on, and we should take that seriously" rather than
> pretending that XML is simply glue for other technologies. This may not
> be easy to sell to customers, but it may help us solve their problems.
Well that's why some call XML "post object oriented" (POO) somewhat tongue
in cheek, but only somewhat.