View Source: SGML - Waikato Linux Users Group

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[Acronym] for __S__tandard __G__eneralized __M__arkup __L__anguage.

It evolved from earlier generalized markup languages developed at [IBM], including General Markup Language (GML) and ISIL. Despite the name, it's not itself a markup language, but a description of how to specify one. Such a specification is called a [DTD]; a good example for MetaData. The premier markup language defined in terms of [SGML] is [HTML]. While disregarded in [HTML] for a long time, the philosophy of [SGML] is that documents should be described in terms of their structure, rather than the "document image". They can then be displayed or output in any form appropriate for any media.

However, the standard is excessively complex, so no [SGML] parser to date supports all of the standard's features. Many of these were added to cater to humans writing [SGML] documents manually, but more and more markup is machine generated. This situation eventually led to the creation of [XML].

sgmlnorm(1) can be used to check whether [SGML] documents validate against their [DTD]. For example, if a [HTML] file contains a proper document type declaration like

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">

then sgmlnorm(1) can validate it against [W3C]'s __strict.dtd__ and report any violations (such as having text not contained in __<P>__ or __<DIV>__ tags). [Debian] users can install the __opensp__ package to get this and other [SGML] parsing tools. (__opensp__ is the actively developed fork of the old __sp__ - (SGML Parsing) package.)

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CategoryStandards

12 pages link to SGML:

Last edited on Wednesday, December 10, 2003 9:22:44 am by JohnMcPherson

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