Differences between current version and predecessor to the previous major change of SGML.

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Newer page: version 4 Last edited on Wednesday, December 10, 2003 9:22:44 am by JohnMcPherson
Older page: version 1 Last edited on Thursday, July 25, 2002 10:00:52 pm by WikiAdmin Revert
@@ -1,20 +1,14 @@
 [Acronym] for __S__tandard __G__eneralized __M__arkup __L__anguage. 
-SGML (Standard Generalized Markup Language) is a standard for how to specify a document markup language or tag set . Such a specification is itself a document type definition ( [DTD]) . SGML is not in itself a document language , but a description of how to specify one. It is metadata  
+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.  
-SGML is based on the idea that documents have structural and other semantic elements that can be described without reference to how such elements should be displayed . The actual display of such a document may vary ,  
-depending on the output medium and style preferences . Some advantages of documents based on SGML are:  
+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].  
-* They can be created by thinking in terms of document structure rather than appearance characteristics (which may change over time ).  
-* They will be more portable because an SGML compiler can interpret any document by reference to its document type definition ( [DTD]) .  
-* Documents originally intended for the print medium can easily be re-adapted for other media , such as the computer display screen.  
+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  
-The language that this Web browser uses, Hypertext Markup Language ([HTML]), is an example of an SGML -based language. There is a document type definition for HTML (and reading the HTML specification is effectively reading an expanded version of the document type definition)
+ <!DOCTYPE html PUBLIC " -//W3C//DTD HTML 4 .01//EN">  
-SGML is based somewhat on earlier generalized markup languages developed at [IBM ], including General Markup Language (GML ) and ISIL
+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.)  
-- ----  
-[XML] is a simplified version of [SGML] when the discovered that noone understood [SGML], and only used a handful of features.