Re: XML and GNOME community

[Bart Schuller <schuller+gnome lunatech com>]

On Fri, Jun 05, 1998 at 02:31:22AM -0400, Elliot Lee wrote:
> On Fri, 5 Jun 1998, Elliot Lee wrote:
> > Could you recommend a direction for GNOME to start in for using XML as the
> > format for saving & loading documents?
> 
> Oops, I just realized this may be a bad question to ask (i.e. I'm clueless
> here! :). Is XML the format to use, or is RDF - what's the relation
> between the two, what's the big picture?

XML is not a format, it's a syntax. Just like SGML. So when people talk
about "using XML" for something, it's much like saying "The 8-bit byte
should be the basic building block of all GNOME apps".

XML as a syntax has the advantage that nesting relationships are easily
expressed. It's much better suited for hierarchical data than
gnome-config.

But to move beyond the content-free buzzword stage, we need to look at
specific applications of XML. Some ideas:

- Documentation. DocBook is SGML, so counts as even better as XML. Only
  when people want to parse documentation using home-grown tools it
  might make sense to convert them to XML first. There will be an XML
  DocBook, but in the mean time one can use the "sx" tool to convert
  SGML to XML.
  I see no reason to abandon the DocBook SGML DTD.
- Configuration file format.
  <GnomeHelp>
    <bookmarks>
        <file>.gnome-help-browser/bookmarks</file>
    </bookmarks>
    <Placement>
        <Menu top/>
        <Toolbar top/>
    </Placement>
  </GnomeHelp>
  This way one could have the contents of the whole .gnome directory in
  one file. But if the current format works, why switch?
- User Interface Builders.
  XML is a pretty good nail, no need to reinvent it. Let people reuse
  the growing number of very good hammers available for XML.
- HTML replacement in the XmHTML widget.
  Most of the efforts that try to display arbitrary XML as a web page
  converge on the use of CSS stylesheets (and maybe some extras). It
  makes sense for any web rendering engine to support CSS to the fullest,
  so that HTML can be expressed as a set of specific stylesheets, only
  making use of very generic flow objects like <DIV> and <SPAN>. That
  way XML support comes naturally.
- RDF. (Elliot mentioned it)
  From the web page (http://www.w3.org/RDF/):
    Example applications include sitemaps, content ratings, stream
    channel definitions, search engine data collection (web crawling),
    digital library collections, and distributed authoring. 
  It looks like a bit too Web specific for GNOME.

    The bottom line

Use XML whenever you have a data structure that is not inherently binary
in nature (like image data). Define your own set of element definitions
("tags") for the application at hand. Those definitions can be in the
form of informal instructions, a DTD or an "XML-data" document (hmm the
w3.org server won't let us have it anymore).

It's probably not a bad idea to keep an eye on the development of new
applications of XML (that is, sets of tags and their meanings).

No need to rush into statements like "GNOME endorses XML", as they carry
no meaning.

-- 
The idea is that the first face shown to people is one they can readily
accept - a more traditional logo. The lunacy element is only revealed
subsequently, via the LunaDude. [excerpted from the Lunatech Identity Manual]