Re: ISO standards

At 04:17 PM 23/7/96 -0700, David Perrell wrote:
>I've been presented with the following logic:
>
>    PostScript is a publishing standard.

Not exactly - it is a page layout language. It is an industry standard (and
proprietary).

>    SGML is a document markup standard.
>    HTML is a document markup language.
>    Therefore, PostScript is out of the picture.
>
>This leaves me wondering: (1) For what purpose are documents being
>marked up if not for some form of publishing? (2) Is there no
>relationship between existing publishing standards and the markup of
>documents for publishing?

SGML is a generic markup language, that is it is intended to mark the
content of documents independently of any form of presentation. PostScript
is a means of presentation of languages. Publishing of documents may well be
to paper, in which case you simply use the generic markup in conjunction
with some kind of 'style sheet' to produce a printed form (perhaps using
PostScript to drive the display device). But there are other forms of
publishing too - electronic publishing, for example - you might want a
completely different way of presenting the content, entirely unrelated to
the printed page paradigm. Because SGML aims to be independent of
presentation, you can do this too, even if the method of presentation hasn't
been invented yet. The relationship between markup of documents and standard
methods of paper publishing depends on the semantics of the documents. There
is now a standard for expressing such relationships (DSSSL), but how
precisely a document is presented depends on innumerable factors. The value
of generic markup is that you aren't tied to one presentation.
   And of course, publishing is not the only purpose for marking up
documents - you might want to automatically process many documents to
extract particular pieces of information (as with a database), or any number
of other uses which don't necessarily involve publishing per se.

Paul Treadaway

Received on Wednesday, 24 July 1996 14:12:36 UTC