Introduction to SGML

A new way to think about text

• structure not formatting
• portable representation
• enhanced content

What it is

• Markup in plain ASCII
• ISO 8879:1986
• 332 definitions; 70 basic
• history: GML
• DTD, Entity, Element

History

• Specific Coding (format-17)
• late 1960's: Generic Coding (header)
• 1969: GML (IBM, Goldfarb, Mosher, Lorie) for law offices
• Invented 1974 by Charles F. Goldfarb
• 1978: ANSI committee
• 1983: GCA standard
• 1985: final ISO draft
• 1987: DoD CALS

Acronyms

• SGML - Standard Generalized Markup Language
• DSSSL - Document Style Semantics Specification Lang.
• DTD - Document Type Description
• CALS - Computer-aided Acquisition and Logistic Support
• ISO - is *not* an acronym

What you can do with it

• smart editing
• automatic generation
• databases
• typed searching
• output processing

What it looks like

<tag> </tag>
<tag attr=value>
&lt; &amp; &gt;

sgml-lecture.sgml

<!doctype slideshow SYSTEM "slides.dtd">
<slideshow>
<title>Introduction to SGML</title>
<author>Mark Eichin, SIPB</author>
<date>IAP 1998</date>
<slide>
<header>A new way to think about text</header>
<bullet>structure not content</bullet>
</slide>

slides.dtd

<!ENTITY lt SDATA "<">
<!ENTITY gt SDATA ">">
<!ENTITY amp SDATA "&">
<!element slideshow o o (title?, author?, date?, slide*)>
<!element (header|title|author|date) - - (#PCDATA)>
<!element slide - - (header, (bullet|subbullet|url|raw|example)+)>
<!element bullet - - (#PCDATA)>
<!element subbullet - - (#PCDATA)>
<!element url - - (#PCDATA)>
<!element raw - - (#PCDATA)>
<!element example - - (#PCDATA)>

sgmlspm

• perl interface to add code to tags
  sgml('<SLIDE>', sub { &inittag;
  output "%%Page: $pageno\n";
  output "($savetitle) showtitle\n";
  output "($pageno) showpageno\n"; $pageno++; });
  sgml('</SLIDE>', sub {
  output "finishpage\n";
  });

HTML

• Simple DTD - 70 elements
• historically, no invalid pages
• comment syntax
  <-- comment -- -- another one -->

Docbook

• http://www.oreilly.com/davenport/
• Software Documentation
• Very rich (400+ tags)
• Industry Consortium

Other DTDs

• QWERTZ
• sgml-tools/linuxdoc
• TEI (Text Encoding Initiative)

DSSSL

• R4RS Scheme
• Document Style Semantics Specification Language
• ISO/IEC 10179:1996

XML (Extensible Markup Language)

• W3C effort
• Stripped down SGML
• XML parser in java
• Web Spiders/Robots
• Microsoft CDF (Channel Definition Format)
• XSL (Extensible Stylesheet Language)

Athena tools

• add sgml
• jade, nsgmls, stylesheets

Commercial Tools

• Frame 5.5+SGML (?)
• WordPerfect 8
• OmniMark (LE)

Other Stuff

• HyTime: ISO 10744
  Hypermedia/Time-based Structuring Language
• mathematics
• MIME-SGML
• OCLC, LOC
• Chemistry, Physics, Astronomy

Pointers

• http://www.mit.edu/iap/iap-sgml.html
• http://www.sil.org/sgml/sgml.html
• ftp://ftp.lysator.liu.se/pub/sgml/psgml-1.0.1.tar.gz
• http://www.jclark.com/jade/
• comp.text.sgml

Last processed: 1998-02-03T02:47:11