Re: What is SGML?

[Glenda Jeffrey <jeffrey -at- HKS -dot- COM>]

Mark Levinson (mark -at- sd -dot- co -dot- il) wrote:
: SGML tags your text according to characteristics that are not
: typographical but structural.  For example, rather than labelling
: a particular string of words as 10-point New Century Schoolbook
: italic centered, it might label them as a figure caption-- if
: that's what they are-- without dictating what a figure caption
: looks like.

Great explanation!

: Distributed in this form, texts can easily (with the help of
: appropriate software) be printed out or displayed according
: to the capabilities of any particular printer or display device.
: (All you need, for the figure caption, is a program at the user's
: site that dictates a particular representation for figure captions
: along with representations of all the other structural elements of the
: text-- body text, headers of various kinds, emphasized words, etc.)  Any
: exact resemblance between the typography at the author's site and the
: typography at the reader's site is coincidental.

This is certainly true with HTML (which is used on the World Wide
Web), since each Web browser (and even each user of each Web browser)
can set up his or her own typographical interpretation. However, there
are browsers (not Web browsers - yet) in which the author can dictate
quite forcefully which fonts are used.

This is a different animal from things like Adobe Acrobat, in which
the entire page layout (including but not limited to typography) is
frozen by the author. With SGML, the author has little control over
online page layout because neither SGML nor the online document
browser has any concept of a page -- and that's because online, a
"page" is a dynamic thing. Whenever you resize your window, you resize
the "page," so the layout must be dynamic to account for that.

The document designer CAN have precise control over PAPER page layout
in a general sense, depending on the composition engine -- for
example, the designer can specify headers and footers, etc., and there
are ways to control page breaking and figure positioning. But all this
is highly dependent on the composition engine and is really not part
of SGML.

Anyway, I could go on and on -- but I hope this helps the person who
was looking for the definition.
--
Glenda Jeffrey                                     Email: jeffrey -at- hks -dot- com
Hibbitt, Karlsson & Sorensen, Inc                  Phone: 401-727-4200
1080 Main St.                                      Fax:   401-727-4208
Pawtucket, RI 02860