Helpful Information

Category: XML

Basic Question

I've read a little bit about XML, and I think I understand what it is, but I have yet to see a need for it. What exactly is it for?

ryn�

XML itself is a specification for developing languages. Per se, XML itself is not very useful.

However, several XML languages are highly useful indeed. For instance, XHTML is the XML version of HTML. SVG is an XML language for Scalable Vector Graphics (and very nice ones, too). XSLT transforms from one language to another.

Outside of presentation languages such as SVG, the largest application of XML is for creating languages for storing data, and conveying that data between applications (such as a server and a browser, in one very limited sense) in a standardized format.

Does this help? :)

Ah, Alex, I remember you from the days of the wsabstract forums. Glad to finally hear from you again! Thanks for the response.

Some popular examples of XML applications outside of W3C:

RSS - perhaps one of the most popular XML apps, it describes news feeds. Odds are you've heard of it before. Even W3C publishes their DOM news in an RSS feed. It utilizes the W3C-standard RDF XML application (meta-data basically) and some of the Dublin Core (additions to describing meta-data).

Chemical Markup Language - some chemists made this up to describe chemical compounds and stuff in XML. Also very popular.

I've used XML in a project I did for describing essentially test results for students taking part in math competitions. I then used XSLT to output HTML in a myriad of ways. Because of the nature of the current XML applications available, storing data as XML immediately has advantages. I could transform a document into XHTML for display in a web browser, but transform the same document for display in WAP-enabled cellphones with WML, and also convert it to PDF via an XSL-FO intermedate step.

Star Office 6.0 (and OpenOffice.org 1.0 which is more or less the same thing) use XML for their standard file format. To be precise they use zipped XML archives which you can open with WinZip and examine the raw XML. If you're really clever you can write an application to transform the raw XML into an HTML page, so that the document files can be read by a browser rather than the creating application - something I want to do when I get the time.

Oh - and the XML files are much smaller than, say Word docs. Not terribly important if you have broadband but if you've ever had some kind soul send you a 2.5Mb Word document on a dial-up connection you'll understand what I mean.

patrick

PS: Open Office is pretty good as an Office suite anyway - and it's free - as in "free beer"