RE: Lout, is it too late?

[Henrik Martensson]

I pushed the wrong button and sent the following stuff to the wrong email
address a few days ago. Better luck this time, I hope. Here goes:


It would probably be smarter to let sleeping threads lie, but I have a touch
of insomnia tonight, and I just can't resist this.


I'll skip the stuff that was not directly related to XML, since others have
already answered those questions better than I can.


> Hello All,

<snipped lots of not-XML stuff>

> Now, what I wish to see for a future Lout is a system redesigned to
support
> the emerging
> documentation and database standard--XML. HTML is now redesigned to
> XML-based
> XHTML. DocBook went through the same process to use XML. There is hardly
any
> new
> wordprocessor currently not based on XML, name them MSWord, WordPerfect,
> AbiWord,
> StarOffice, KWord etc.
> All new configuration files are being redesigned to use the XML. Database
> systems are
> leaving the propriety formats to XML.
> So my question is, is it too late to consider a redesign of the Lout to
XML
> format? Parsers
> are freely available and new onces are coming.
> Where do you want to go today?

Probably not to an XML format. It is a mistake, albeit a very easy one to
make, to believe that using XML syntax would necessarily make Lout more XML
friendly. There are several non-XML formatting languages in use for
formatting XML today. For example:

* CSS
* DSSSL
* MIF (FrameMaker)
* LaTeX
* Lout (!)
* WordPerfect

It would be nice to have a standard formatting language, instead of a lot of
different ones, but one such language, XSL, is on the way. (BTW, DSSSL is
such a standardisation effort, only it failed to take root.) The fact that
XSL is XML compliant makes it easy to sell, but from a usability point of
view, it is immaterial.

>
> <lout filename = "Hello.lt">
> <sysinclude>
>     <file>document</file>
>     <file>figure</file>
> </sysinclude>
>
> <document>
> Hello, Lout!
> </document>
> </lout>
>
> or better still...
>
> <lout filename = "Hello.lt", comment = "My first Lout program">
> <include directory = "system"> // to the system directory or "current" to
> mean the current directory.
>     <file>document</file>
>     <file>figure</file>
> </include>
>
> <document>
> Hello, Lout!
> </document>
> </lout>
>
> How about the section example above
> <section tag = "dfs", title = "Depth-first search">
> This should be it...
> </section>
>

>From an XML perspective the formatting language described above would be
very unsuitable for writing documents in, simply because it contains
formatting markup instead of descriptive markup. (I won't go into all of the
reasons for this, just trust me!)

This means it would still be necessary to translate from the (presumably
descriptive) source format, to the formatting language. (By the way, this is
the way the XSL formatting language works.)

This transformation would not necessarily become one whit easier just
because the output is XML compliant. For example, XSLT, a popular XML
transformation language can produce Lout markup just as easily as it can
produce XML markup.


> About from being more elegant and easier to follow, parsing will be very
> easy
> and faster compared to the current Lout format.

I do not agree that the XML markup above is easier to follow than Lout
markup. It is mostly a matter of what you are used to.

Also, it really does not matter. In the XML world, we wouldn't be interested
in looking at the Lout (or XLout, if we had an XML version) code, just as we
aren't interested in
looking at the Postscript code produced by the formatting engine. (The
exception, of course, is when debugging, something ordinary users should
never be required to do.)

Normally, we would only be interested in the source document and the style
sheet (XSLT or some other language).

>
> XML-based mathematics format, MathML, is already defined (a standard) and
> new web browsers like the Mozilla have already supported it.
> Mathematica now uses this format and the scope of Lout will be unlimited
> when this format is supported. We may execute equations right from text
> editors using Mathematica and others systems that are bound to support
this.

It would be the job of a style sheet to define transformations from MathML
to Lout, just as with other MathML systems, for example PassiveTeX, a system
that transforms XSL, and MathML, into LaTeX.


>
> With the XML-based Lout, the conversion from and to any wordprocessor
could
> be
> easily done. This is the future, a common format for all.

The planned common formatting format is XSL. I do not think that we need
another. (XSL can cause enough trouble without any help from other common
formats.)

However, being an XML nerd, there are some things I would love to see in
Lout, that would be of benefit to... well, to me, at least:

* Unicode character support would make it unnecessary to translate
  characters like å, ä, and ö in XML text strings to Lout character
  codes. XSLT really sucks at this sort of thing, so it would be
  a big help if one didn't have to do it.

* Chapters and sections would be easier to handle if they used a
  recursive format along the lines of

  @Section
  ...
   @Section
   ...
   @End @Section
  @End @Section

  This would make it easier to reuse document fragments in different
  contexts.
  For example, a section in a chapter could be reused as a subsection,
  or as a  chapter in its own right, in other documents.

* I would like the ability to specify page templates with multiple
  text boxes, and then assign a text flow to a box in a template.
  (If you are familiar with, for example, the FrameMaker MIF format,
  you know what I mean. I would like a simpler syntax than MIF uses
  though.)

* A set of XSLT style sheets that transform XSL into Lout. This would
  turn Lout into a real contender in the XML arena. Suddenly, Lout
  would become usable as a back end to all XSL based formatting systems.
  (This is the same thing PassiveTeX does with LaTeX, the difference being
  that the conversion from XSL to LaTeX is done with LaTeX macros.)

* An XHTML back end for Lout. XHTML is the XML compliant next generation
  HTML. It works in most current HTML browsers. In combination with the
  XSLT style sheets mentioned above, this would mean it would be possible
  to use Lout to convert from XSL to Postscript, PDF and XHTML,
  which would cover most peoples formatting needs. (At least my needs!!!)


To sum it up, the changes I would like to see in Lout, i.e. Unicode support,
recursive sections, high level commands for building page templates with
multiple text flows and XHTML output, are changes that I think would benefit
anyone that is interested in using complex layouts and/or publish formatted
documents online, regardless of whether they use XML or not.

Any XML specific adaptations can, and in my opinion, should, be done using
an XSLT style sheet that converts XSL to Lout.

Of course, to be realistic, such changes require a lot of work, and the
general interest in XML in the Lout community is probably low.

It has been nice dreaming a bit though. I think I'll be able to go to sleep
now.


Henrik Martensson
GNOSIS-Gruppen
Technical Documentation Services
URL: http://www.gnosisgruppen.com/