HTML+ support for eqn & PostscriptDave_Raggett <firstname.lastname@example.org>
From: Dave_Raggett <email@example.com>
Subject: HTML+ support for eqn & Postscript
To: firstname.lastname@example.org, email@example.com
Date: Mon, 14 Jun 93 10:36:40 BST
Mailer: Elm [revision: 220.127.116.11]
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 > 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 ">" 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.