HTML+ support for eqn & Postscript

Dave_Raggett <>
From: Dave_Raggett <>
Message-id: <>
Subject: HTML+ support for eqn & Postscript
Date: Mon, 14 Jun 93 10:36:40 BST
Mailer: Elm [revision:]
Torben Nielsen says:

> I realize this has come up before, but how about really doing something about
> equation support? There are lots of documents I would like to put into the
> Web, but without support for embedded equations, it's really quite difficult.
> Something simple like eqn support would be great. And eqn shouldn't be all
> that hard to parse either.....

Bill Janssen chips in with:

> And I really like to send encapsulated Postcript in my documents... 
> Having ghostscript should make the parsing and layout easy!

Well both of these will be possible with the HTML+ DTD, by using the capability
to embed foreign formats inline in the HTML+ source, e.g.

        <H2>A example of an equation</H2>

        <EMBED TYPE="text/eqn">zeta (s) ~=~ sum from k=1 to inf
         k sup -s ~~~ (Re s &gt; 1) </EMBED>

The browser identifies the format of the embedded data from the "type"
attribute, specified as a MIME content type. Certain characters need to
be escaped using entity definitions, e.g. ">" by "&gt;" in the example.

Building in support for a range of formats has the danger of leading to
very large programs for browsers. This could be avoided by using a common
API for rendering foreign formats, e.g. as functions that take a sequence
of bytes and return a pixmap.

Browsers can then be upgraded to display new formats without changing their
code at all. All you would need is a way of binding the MIME content type
to the function name for that format, e.g. via X resources or a config file.
The functions could be implemented as separate programs driven via pipes and
stdin/stdout or as dynamically linked library modules (Windows DLLs).

How does that sound?


p.s. you can also put the foreign data in a separate file referenced by a URL.