[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] What is XML? (Was: Re: What Clean Specs Achieve)
Tyler Baker wrote: > If XML is not going to be simple, why use XML at all when there > supposedly are much more powerful and well-established standardized > alternatives like SGML in existence that get the job done. This is my understanding: * XML is for information interchange on a large international scale. * SGML was primarily created for internal manuals and specifications. Computationally, SGML has irregular structures that *require* the DTD to be known before the file can be parsed. XML does not have this restriction, it's syntax is independent of the "architecture" or DTD. More than that, this change has had only minimal "reduction" of it's usefulness, i.e., it is harder for harder for humans to diectly author in the language. This simplification has drastically reduced its computational complexity, thus enabling it to be applied in many more contexts. Namespaces is the mechanism to keep all of those contexts from colliding with each other. Architectures is the mechanism that provides the mapping between those contexts. It is this greater applicability that is driving the need for namespaces. This *is* new. No existing document interchange "syntax" has gotten this far, I would say that the INI file format and the CVS file format would have been the runners-up to XML. The complexity to which a computer program express itself using the XML syntax is far greater than CVS or INI syntax. Think of XML as a better "CVS" or "INI" format, not as a weakened SGML. This is the better metaphor. See, SGML and most other "exchange" mechanisms in the past have tied the "syntax" and the "semantics" together. XML is different. It clearly defines the syntax and leaves the "semantics" to the application of the technology. The "DTD" is optional. And Architectures allows you to have more than one DTD. This way each party to the communication can have their own interpretation of the exchange. Seperating these two is a _hudge_ leap forward in software systems. Anyway, this is my view of things. I hope it helps. :) Clark Evans xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
|
PURCHASE STYLUS STUDIO ONLINE TODAY!Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced! Download The World's Best XML IDE!Accelerate XML development with our award-winning XML IDE - Download a free trial today! Subscribe in XML format
|