XML tutorials

What tutorials are available for those beginning to use Tcl with XML? The sassy answer is to attend one of the Tcl Conferences, because Steve Ball is reliable about presenting this subject. Steve's moving some of this material on-line [L1 ], and some is already available on request from Zveno.

If you can't wait for those opportunities, read these on-line presentations of XML management with Tcl, all of which are accessible to XML beginners:

  • "Programming XML and Web services in TCL" [L2 ]
  • e4graph has complete XML input and output facilities, and they are reflected in the Tcl binding (Jacob Levy, 05/15/2003)
  • A tDOM Tutorial

TV Isn't XML like html where you can invent any label you want to any nesting level, where you are left to invent the meaning and the interpretation yourself, too? Of course it means you can have parsing of such labels, maybe listing the lot of them, a syntax definition, and hopefully standard readers and label sets and meanings. Is there much to actually learn about xml itself, I mean one can invent many special meaning labels, like html, and pretty printers and such, but xml itself is an open ended 'language' with a bit akward to type but easy enough hierarchical stucture, or did I miss a few evolving versions?

escargo Part of the subject involves schemas that describe the allowable structure of the XML documents. Schemas can be described as document type definitions (as in SGML) or with the newer XML schema standard (the specifics of which I don't recall). An XML document can then be parsed and compared with the defining schema to determine if it is valid or not. (Some parsers are validating parsers and some are not.) The processing of XML documents can either be done as parts are being read (event-driven processing, e.g., SAX for Java) or once everything has been read in. Depending on the size of the whole XML document, one scheme might be better than the other.

NEM XML itself is fairly simple to get to grips with. What takes longer to learn is the huge number of related technologies that go along with it: XSLT, XPath, XPointer/XLink, etc etc etc. A new X-technology seems to come out every week. XPath is probably the single most useful of these, as it allows for quite simple selection of elements in a document (it's kind of like the SQL of XML). tDOM has great support for XPath.