[tlug] A question about XML

["Stephen J. Turnbull" <stephen@example.com>]

burlingk@example.com writes:

 > Are there any really good XML tutorials on the web, or perhaps a book
 > that is actually useful?

No.  That's like asking "are there any good tutorials on first-order
logic on the web?"  Sure, you can build all of mathematics out of it,
but unless you are Bertrand Russell YAGNI.  XML is a very low-level
specification that basically amounts to Lisp data with multicolored
parentheses, where the colors must nest properly.

The question to ask is "are there any good tutorials about using XML
to do ... ?"

 > Also, which libs do people preffer for dealing with XML?

Depends on whether you've got a DTD or not, and if you do, which one.
If it's WebDAV, I use neon.  For things like SOAP and XML-RPC (which I
don't use) there are plenty of libraries.  There are DOM-oriented
libraries.  There are AJAX libraries.  expat and libxml2 are excellent
low-level C libraries, with slightly different advantages.  In Python
I use ElementTree a bit.

 > The project would involve loading objects into a dynamic list.  I do not
 > think I want to deal with the XML file in real time, as I am not sure
 > how fast that would be, but rather load the data into memory, then save
 > it to the XML file at save points.

XML is intended as a serialization format for annotated trees.  There
is some generalization so that DAGs are easy enough to treat; anything
more complex is going to require a lot of design on top of the XML.
Normally in memory it's all implicit in the graph structure; what XML
DTDs and libraries do is take the bookkeeping off your hands.