The XMLSGML Conundrum

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TO USE OR PRINT this presentation click : http://videosliders.com/r/344 • ============================================================== • The XML/SGML Conundrum Presented by Joseph V. Gangemi Senior Consultant J.V.G. Consulting Services ©2005 • ,Agenda Compare aspects of XML and SGML • Explore rational for choosing between them Discuss affect of XML on publishing applications Some personal thoughts on SGML Where do we go from here? Audience participation is encouraged J.V.G. Consulting Services © 2005 • ,What is a Conundrum A question or problem having only a conjectural answer • Should I use SGML or XML? • Do I need a DTD or an XSD? Will publishing survive the XML marketing hype? An intricate and difficult problem Does XML address the needs of my application • J.V.G. Consulting Services © 2005 • ,What is SGML? Markup Language for Text Processing • ISO Standard 8879 • Syntax rules for defining a markup language Does not include a set of tags • Full-featured to support a wide array of applications Perceived as complex, but in reality, text applications are complex Not all features are used in all applications • J.V.G. Consulting Services © 2005 • ,What is XML? Subset of SGML • Designed for the transport of text over the Internet • Extensible Markup Language meant to complement HTML More generic; not a formatting language • Structure rather than format oriented Less complex from a programmer’s perspective Not necessarily the user’s! • J.V.G. Consulting Services © 2005 • ,The XML Myth XML does not require a DTD or XSD • Yes and No • From a programming perspective, the DTD or XSD is optional (for some applications) This is also true for SGML • From a practical design perspective, IT IS MANDATORY No inherent benefit to XML (or SGML) without one If you cannot define and enforce a tag set, calling it a language is a misnomer. • J.V.G. Consulting Services © 2005 • ,Choosing between XML and SGML (Putting aside the marketing appeal and looking at the technology) • ,XML / SGML Feature Sets Review SGML features omitted from XML • Original Intent of feature • Reason for omission from XML Effect of Omission on Publishing Applications How is user affected? • How is product vendor affected? J.V.G. Consulting Services © 2005 • ,SGML Declaration Describes the processing environment in which the document can be processed. • Identifies character set • Specifies features required for successful processing Purely technical information User has minimal, if any, awareness of it • Product vendors benefit by being able to tailor product to each client’s application environment Once environment is defined for an organization, it has minimal value (except, of course, to the vendor). XML has a defined environment (World Wide Web) In effect, it has a built-in SGML declaration • Processing is restricted to the defined environment J.V.G. Consulting Services © 2005 • ,SGML DCL Features XML defaults the following features to NO • (which means they are not supported) DATATAG • OMITTAG RANK LINK CONCUR SUBDOC SHORTREF J.V.G. Consulting Services © 2005 • ,Datatag A string of characters that acts as both data and the end-tag of the currently open element. • Actually defined poorly since its purpose is to delimit repetitive elements. If it closes an element, it inherently opens the next one too. Never implemented because short references became a better way to achieve same objective. Considered an irrelevant technique and is not supported by vendors. J.V.G. Consulting Services © 2005 • ,Omittag Refers to tag minimization • Start and end tags can be omitted under certain parsing conditions • Method of reducing the character count or physical size of a file back when it meant something to do that  Vendor products make the feature moot. J.V.G. Consulting Services © 2005 • ,Rank Rank IS rank • Irrelevant concept, poorly conceived, badly defined, and eschewed by we elite purists in the industry • Attempt to take linear tagging for typesetting and treat it hierarchically Even Charles wants to see this gone! No relevance to vendor or user J.V.G. Consulting Services © 2005 • ,Link Method whereby a process can be associated with

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