Resource Library: Multimedia/Resource Library: Multimedia.iso/hypertxt/msdos/montana0/sgml

Text File | 1993-03-05 | 9.0 KB | 169 lines

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                                                        The Florida SunFlash

          SGML - Standard Generalized Markup Language

SunFLASH Vol 43 #5                                                 July 1992
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This is an article by James F. Salois that was posted to the Publish mailing
list. -johnj
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            From: [e-mail] (James F. Salois)

1. SGML - Standard Generalized Markup Language - is an ISO (8879) standard
for the markup of text. Unlike the procedural markup used by most
proprietary word processing and publishing systems, SGML employs a
"descriptive" markup. Rather than describe how each element of text is to
be formatted, SGML describes only the elements. For instance:

[chapter]
        [title]What is SGML?[/chapter]
        [par]SGML is an ISO (8879) standard for the...[/par]
        [list]
                [item id=i1]a brief description about what SGML is[/item]
                [item id=i2]recommended references to get further...[/item]
                [item id=i3]Products that support it.[/item]
                [item id=i4]How does it fit into publishing...[/item]
                [item id=i5]Comments about SGML, usefulness...[/item]
        [/list]
        [par]A discussion of how to cross reference might be covered in
             item [xref idref=i1] above.[/par]
[/chapter]

Several things you should note about the above fragment of SGML:

* The use of "chapter", "title", "par", "list" and "item" is defined by me,
  as the creator of this document type. SGML allows for the definition of
  "arbitrary" document types through a "Document Type Definition" or DTD.
  This allows for DTDs to be created and applied to very specific document
  or publishing problems. E.g., in your application, you may elect to use
  the following names for these elements: "ch", "chhd", "p", "l", "li".

* The syntax used above ([tag_name][/end_tag_name]) is also application
  specific. Basically, you can vary the characters used to delimit tags and
  optionally omit start or end tags. These features of SGML are designed
  to allow rapid and efficient keyboard entry of markeup, where specialized
  SGML editors are not available.

* The indented presentation of the fragment above is for readability only,
  and is not a feature of SGML, though whether an SGML document is stored
  as above or run-on into one long string, makes no difference to SGML.

* The fragment above only describes "what" is contained. No information
  about "how" to process the fragment above is evident (I purposely
  avoided saying '"how" to _format_ the fragment above...'; see below).

Finally, two comments about what SGML is NOT:

        1. SGML is NOT a formatting language.
        2. SGML is NOT a system. In of itself, SGML does nothing. It is
           simply a language for describing documents, or as I prefer, for
           describing _information_.

2. References:
        There is an excellent bibliography on SGML and related subjects
        (such as DSSSL and HyTime), but it is far to large to post here.
        Therefore, I'll give you an ftp to check out:

<SGMA>  ftp.ifi.uio.no:/pub/SGML/bibliography

        if you have trouble connecting, let me know and I'll see about
        mailing you a copy.

3. There are a growing number of products which support SGML in a variety
   of applications. Some products are author-only SGML editors, others have
   publishing components which will compose and print SGML marked up
   documents. Still others are available for on-line viewing (browsing) of
   SGML documents. There are also products which interface with database
   systems, taking the view that the information contained in a document is
   best represented or managed in a database. That said, as a vendor of SGML
   software I will refrain from listing specific products in this forum.

4. SGML is ideally suited to represent small to extremely large documents
   which are (or should be)
        * well structured,
        * information dense,
        * subject to frequent and/or multiple revision,
        * to be exchanged with internal/external suppliers or
          customers,
   and/or
        * have long lifecycles,
        * have a high degree of content overlap,
        * appear in several different styles.

   In a publishing environment where some or all of these criteria are
   evident, SGML is used to identify the information elements of a document,
   and to ensure the proper organization of those elements. Depending on the
   sources of information and how/if the information needs to be managed,
   SGML documents may be fragmented and put under the control of a DBMS.

   In an SGML based publishing environment, the emphasis is placed on
   gathering, synthesizing, assembling and managing INFORMATION. Once the
   information is identified and assembled, any of a variety of
   applications, including composing for print, can be applied to it.

   The key here is the separation of the authoring (information creation)
   process from the composition (or any other) process. SGML documents
   contain no instructions as to how a document should be composed. This allows
   documents to be managed independant of the specific composition system.
   It also means that if a particular document is destined to appear in
   several different printed forms, the content of the document needs only
   be stored once. More importantly, to apply a different style
   specification, does not involve direct editing of the document itself.

   The separation of style and content inherent in SGML also facilitates
   interchange. Documents are exchanged free of the compositional codes
   native to the original authoring system. For instance, if I created this
   message in WordPerfect, and you did not have a WordPerfect system, you
   would not be able to read it. If I sent you the message in SGML,
   however, at the very least you would be able to read it using your
   favourite ascii editor. If you had an SGML publishing system (not
   necessarily the one I use) you would also be able to print it according
   to whatever style(s) you specify.

5. It is clear to me that SGML has a very bright future. We are seeing a
   transformation in the publishing industry. The problem that many people
   are finding is no longer one of getting print on paper; the problem is
   identifying and getting control of the information which is your
   organization's most important asset. More and more, organizations can
   ill afford to have their publishing processes function as islands,
   producing material which has been separated from its source and
   identification. With SGML we now have a means of identifying, tracking,
   and managing our information throughout the authoring process, right up
   to the moment it is transformed into print. More importantly, the
   publishing process is no longer a dead-end process. Since authors are
   working with "live" information as they create their documents, they
   have the means to close the information loop, providing valuable input
   back into the organization's information base.

   One last comment before I get off my soapbox (ok, two). One of the most
   appealing features of SGML is its non-proprietary, vendor independent
   format. It means that, for the first time, complete, detailed documents
   can be created and exchanged independent of the hardware or software
   used. This non-proprietary format lead to my second comment concerning
   longevity. Since SGML represents the INFORMATION contained in a
   document, I know that documents created today in SGML will be just as
   viable in 5 or 50 years, long after today's computers and printers have
   become obsolete.

-------------------------------        -----------------------------
James F. Salois                        ArborText, Inc.
Director of Product Marketing          1000 Victors Way
ArborText, Inc.                        Ann Arbor, MI 48108
                                       Ph. [phone]
[e-mail]                      Fx. [phone]
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