----- Original Message -----
From: "Stephen White" <spwhite / chariot.net.au>
> Just a brief side-track... but I'm seeing "XML" everywhere and I just
don't
> click onto why everyone's talking about it.

An anecdote: My first job out of college was for a used-parts "network."
Someone calls a used-parts dealer looking for some strange part.  The dealer
says, "No, I don't have it in stock.  Let me check the network."  He puts
out a message "Hey, anyone got part XY123Z?"  Hours or days later, someone
finally gets around to reading their messages and says, yeah I have that."
A very slow way to do business.  So we told these guys, "send us your data.
Then people will check our network, see you have the part, and never mind
reading a zillion messages.  What's more--we'll send you a message that
they're looking for it."  That went over pretty well, but they all kept
their databases in a different format.  I got everything from dBase to Unix
tar-floppies to IBM EBCDIC tapes.  No two alike.  I got the joyful job of
massaging their data, often by hand (I didn't have Ruby then--see I'm on
topic!) with a text editor, so it could be imported into our database.  If
all their databases could have exported to XML with a common DTD, or a DTD
that could be translated from, my job would have sucked a lot less.

> It seems to me that XML is a really weak SQL, with the difference that
> anything is supposed to be able to parse it... but ends up with everyone
> having to create and re-create a database in their code instead of just
> using SQL or an external database.

XML excels at being the esperanto of data formats.  In itself, it may or may
not be the best format for any particular application, but it's a great
common ground.  It's not a query language like SQL.  I've seen XML databases
that could be queried with SQL though.  The point is: do you really want to
invent yet another data file format?

> I don't even grok why expat is 300k of C source to find <tags>, so that
> gives you an idea how little I know...

It does a lot more than that.  The XML library I wrote for Delphi is less
than 30k, but it doesn't do validation and doesn't have all the same tag
access methods (although I like the ones it has--it's on my list to convert
to Ruby).

Brent