Re: Format Negotiation in Practice [Was: Versioning HTML at the server]

Earl Hood (
Wed, 19 Oct 1994 06:39:48 +0100

> What we really, really need is:
> 1) A "text/sgml" type that allows one to send the information, the
> stylesheet, and the DTD.

The content type is not that simple is the stylesheet is not in
SGML. You'll probably need to use a multipart/mixed.

> 2) A stylesheet definition language (DSSSL? I don't know anything
> about it).

How would the language support differing display devices: text,
monochrome, color, displays for the deaf and blind?

> 3) A parser in every client.

Alot of data to transmit when I connect to other-side of the world. I
think supporting SGML directly will be nice, but extra data is required
during transmission (the declaration, the DTD, the stylesheet, and the
document instance). For big DTDs (and subsequently big stylesheets)
this can be a pain. I'd hate having to wait for the HTML DTD to
be sent to me evertime I retrieved an HTML document.

(One solution for speeding up transmission would be to adopt real-time
compression/decompression algorithms into the HTTP protocal. However,
I do not know the server-side impact of such an implementation.)

> Now, we don't have these facilities here now, so I'll tell you how I
> solved this problem in DynaWeb(tm). DynaWeb(tm) does on the fly
> conversion from SGML to HTML (or to be precise, from "books" created
> by DynaText(tm)). The conversion process is controlled by stylesheets,
> and one can name stylesheets in a manner similar to forms:

Who'll need anything from EBT, if free WWW clients adopt SGML :-)