Logical and physical markup (was HTML2: No Plain List etc)

Mike Piff (M.Piff@sheffield.ac.uk)
8 Aug 94 10:11:43


Message-Id: <MAILQUEUE-101.940808101143.416@derwent.shef.ac.uk>
To: www-html@www0.cern.ch
From: Mike Piff <M.Piff@sheffield.ac.uk>
Date: 8 Aug 94 10:11:43
Subject: Logical and physical markup (was HTML2: No Plain List etc)

%%>Date:          Sun, 7 Aug 1994 17:09:55 +0200
%%>Reply-to:      Torgeir.Veimo@nr.no
%%>From:          Torgeir Veimo (Sommer stud) <Torgeir.Veimo@nr.no>
%%>To:            Multiple recipients of list <www-html@www0.cern.ch>
%%>Subject:       Re: HTML2: No Plain List of Items in Spec, implications for HTML3

%%>I think that the html document format should be much more structured in the
%%>way it defines markup elements. As I see it, there are three levels of markup
%%>that could be present:
%%>
%%>- character mode markup (bold, italic, subscript etc.)
%%>
%%>- paragraph mode markup (body, heading, listitem, preformated, math, table

inline text math and display math

%%>item etc.)
%%>
%%>- document flow markup (blockquote, listgroup [numbered/bulleted/ etc.],
%%>indentation, tables etc.)
%%>

Surely we also need

- font-changing markup which does not merely change the attributes of the
font, eg, between latin and greek, text and math symbol, etc, incase anyone
should want to mix english and greek or english and maths in the same
document. :->


As an extra refinement, why not add

- document style markup, which activates/deactivates the effects of some of
the physical markup?  There are (at least) two different sorts of markup
going on here:

* Logical.  This determines the logical structure of a document. Examples
are a section
<Section>
...
</Section>
or a link
<Link>...</Link>
or a math environment
<Math>
...
</Math>

* Physical. This determines the physical appearance of a bit of text.
Examples are <Bold>...</Bold>, or the fact that a math section is displayed
rather than inline
<Math>
<Display>
...
</Display>
</Math>
or that a list uses bullets rather than numbers
<List>
<Bullets>
...
</Bullets>
</List>


We also need a mechanism of binding a physical appearance to a logical
structure so that with one environment we can produce a bulleted list,
a displayed math formula, or whatever. Someone has suggested parameter
passing as such a mechanism. Another solution is to allow the document
to define the particular bindings for the structures it intends to use,
or for these bindings to be defined in several different style files,
which define different physical appearances for the same logical document.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Dr M J Piff, School of Mathematics and Statistics, University of %%
%% Sheffield, UK.                    e-mail: M.Piff@sheffield.ac.uk %%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%