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From Ross Gardler <rgard...@wkwyw.net>
Subject Re: Documentv20 --> DocBook
Date Tue, 30 Dec 2003 04:13:52 GMT
Peter Hargreaves wrote:
> On Mon, 2003-12-29 at 22:37, Ross Gardler wrote:
> 
>>Peter Hargreaves wrote:
>>

<snip what="XHTML isn;t about presentation"/>

> Maybe the subset of XHTML adopted for Forrest could be a media
> independent DTD like DocBook is.
> 
> What do you mean by presentational information? For me
> <header>...</header> or <footer>...</footer> would be presentational
> information because its meaning is about layout, and it assumes a media
> type like paper that has headers and footers. However,
> <title>...</title> is not presentational because its meaning is not
> about layout. The skin or style sheet for the media called paper can
> choose to put a title in the footer of the page or in the header.

Agreed.

Take a look at the comparison of XDoc and XHTML that Nicola Ken did 
quite some time ago and I reposted at the start of this thread 
(http://nagoya.apache.org/eyebrowse/ReadMsg?listName=forrest-dev@xml.apache.org&msgNo=9131).

That is the subset we are proposing, it does not (or should not) include 
any presentational information.

>>>9) A central document type must therefore be very rich in its
>>>description of document structure and meaning - without bias toward
>>>media type.
>>
>>Quite the reverse. It should be as simple as possible, semantic meaning 
>>has no place at the presentaional layer, it is only presentation that is 
>>important.
> 
> If its simple then it will undermine the meaning of the original markup
> - so the final presentation will be limited.

Can you give an example of why the presentation will suffer?

> 
>>Can you give us a use case in which we need semantic meaning at the 
>>intermediate stage in order to do anything *other* than effect how the 
>>data is presented.
> 
> 
> Of course ALL markup meanings at the intermediate stage can be used to
> affect the final presentation. But their meanings should not be about
> presentation or layout, So, role="MSc" is OK but align="right" is not.
> The skin stylist should decide left or right and in any case the target
> media might not have a left or a right. e.g. Audio.

Agreed, and XHTML does not allow align="right" whilst it does allow 
class="MSc"..

>>
>>"its main structures correspond to the general notion of what 
>>constitutes a book"
> 
> 
> Ah, excellent point! Note that "book" has two meanings:
> 
> 1) The media type called book. I.E. a blank hard back with a binding and
> blank white pages.
> 
> 2) The content type called book. I.E. a novel or work of reference that
> may or may not be delivered via the media type called book.

Yes, but my point is that not everything can be represented as a book. A 
book is, usually, linear. This section comes after that section. Not all 
materials are, my trainning materials for example. Read my comment that 
followed the above.

>>- I use forrest for training materials. Docbook *could* be used as a 
>>source format but it is not ideal in my domain. I use other formats as 
>>my source that have been designed for the purpose. By converting to 
>>docbook as an intermediate format I will be losing semantic information, 
>>which is something you say I shouldn't do, but something I am now 
>>comfortable with (see above).
> 
> 
> When an author writes a document or book using a DTD that is truely
> media independent - he will have no control of style, layout or
> presentation and should not think of such things. His document might be
> delivered through any of many different style sheets for each of many
> different media types. So, for the author, the cost of delivering
> content to many media types is that he can no longer use style as part
> of his message.

What you say is true, but what you say is "When an author writes a 
document or book using a DTD that is truely media independent".

We are not talking about writing the document or book in XHTML, we are 
talking about writing in the most suitable DTD and converting to XHTML 
as an intermediate format for Forrest. Forrest then gives us the style 
information without having to worry about it.

I will not write my training materials in XHTMl or Docbook. I will write 
them in a specially defined DTD, at that point I am not, as you say, 
concerned with presentation. I'm not looking for an intermediate format 
that gives me semantic meaning because...

>>My point is, *no* (usable) intermediate format will be so expressive 
>>that it can accomodate all users.
> 
> 
> Quite. Equally true for whatever intermediate DTD you choose.

Intermediate is what I said, read again ;-)

>>On the XHTML side of things, the following text from the XHTML working 
>>draft convinces me that XHTML should be the intermediate format:
>>
>>"The XHTML family is designed with general user agent interoperability 
>>in mind. Through a new user agent and document profiling mechanism, 
>>servers, proxies, and user agents will be able to perform best effort 
>>content transformation. Ultimately, it will be possible to develop 
>>XHTML-conforming content that is usable by any XHTML-conforming user agent."
> 
> 
> Yes, an excellent and interesting point. But, hasn't XML sort of
> displaced this approach to some degree? Maybe it will catch up again?

XHTML *is* an XML defined language. XML is nothing more than a way to 
*define* markup languages. It itself is not a markup language. Therefore 
XML has *enabled* this approach rather than displaced it - or am I 
missing your point?

> XML is designed for XML > FO > PDF for instance. But if you try to do
> XML > XHTML > FO > PDF you screw it all up.

OK, this is very important. Why will it get screwed up?

All we are proposing is moving from our existing proprietary docbook DTD 
to a subset of the much more widely available, used and accepted XHTML.

Currently XML > XDOC > PDF works just fine, what will change if we go to 
XHTML?

Ross


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