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Re: Formatting Objects considered harmful


Subject: Re: Formatting Objects considered harmful
From: Håkon Wium Lie <howcome@xxxxxxxxxxxxxxxxx>
Date: Sun, 18 Apr 1999 22:58:53 +0200 (MET DST)

Paul Prescod writes:

 > >   A Web
 > >   of XFO documents can be compared to a Web of HTML documents with only
 > >   FONT and BR tags. 
 > 
 > Not quite: XFO has a concept of "list" and paragraphs are indicated
 > through containers, not line breaks. 

True, FONT and DIV tags is a better comparison.

It's true that XFO has list items, but they are on a lower level of
abstaction than HTML's since they e.g. do not communicate if the order
of the list items is significant or not.

 > I think that if you look at the
 > element types in wide use on the Web, formatting objects are not far down
 > the abstraction ladder from HTML.

Alas, many people consider HTML to be a formatting language and use it
accordingly. This is wrong and W3C tries to educate people otherwise.
Deprecating a bunch of presentational tags in HTML 4 is a clear sign
of direction.

 > In your document, for example, most
 > element types are not very semantic. The only element types in it without
 > FO equivalents are EM, H?, META and LINK.

And TITLE and P (which is more than a generic container). Also, the
note uses classes (byline, abstract, question, answer) which -- if
conventions are developed -- can communicate semantics.

 > It is interesting to note that HTML does not allow you to label your
 > footnotes semantically.

HTML 3.0 had a footnote (FN) element [1].

[1] http://www.w3.org/MarkUp/html3/footnotes.html

Even better, though, was the NOTE element [2]:

  The NOTE element is designed for use as admonishments such as notes,
  cautions or warnings, as commonly used in technical documentation. The
  CLASS attribute specifies the type of the element and is typically
  associated with different graphics such as a road traffic warning
  sign. The graphic can be customized with the SRC attribute.

  Example:

    <NOTE CLASS=WARNING>Please check with the local weather
    service before starting your climb. The mountain weather
    is subject to rapid deterioration. It is essential to
    carry a good map and compass.</NOTE>

[2] http://www.w3.org/MarkUp/html3/notes.html

 > > Publishing semantically rich XML should be encouraged when the 
 > > semantics is globally known, e.g. MathML. Publishing arbitrary
 > > XML should be discouraged. 
 > 
 > Are you saying that we should give up all of the bandwidth, performance
 > and functionality benefits of shipping arbitrary XML to the client?

Unless the semantics of the vocabulary is known on the other side, the
client is worse off receiving arbitrary XML than receiving documents
that have been downtranslated (as in the ladder of abstraction) to
HTML or XHTML. I don't see any significant bandwidth or performance
issues here.

One solution which captures both is to downtranslate your internal XML
to XHTML while retaining the original element types in the CLASS
attribute:

 <p class="question">How come?</p>
 <p class="answer>Because.</p>

As an extra bonus, you remain friendly with 100 million browsers.

 > I would suggest that the solution to the identified problem is for XFOs to
 > move up the abstraction level to a little beyond HTML (i.e.
 > HTML+footnotes+headers+footers, etc.). The right level of abstraction is
 > pretty well documented in common word processors: they all have concepts
 > of footnotes, headers, paragraphs, heading levels, cross-references, etc.

This is an interesting idea. But, given that you are so close to HTML,
why not use HTML (or, more likely XHTML) with a few CLASS attributes?

-h&kon

Håkon Wium Lie             http://www.operasoftware.com/people/howcome
howcome@xxxxxxxxxxxxxxxxx                      simply a better browser





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