Reports from XML Europe 2003

May 21, 2003

Uche Ogbuji and Simon St. Laurent

The annual XML Europe Conference took place in London earlier this May. This article collects together reports from writers Uche Ogbuji and Simon St. Laurent.

Notes from the Exhibit Floor

Uche Ogbuji

XML Europe 2003 put the ongoing energy and innovation of the XML community on display, including actual products on the exhibit floor. There was the usual variety of companies displaying editors, scripting tools, XML databases, training and consulting. One important theme was GUI tools for the unsophisticated user. Companies were showing tools which offered a variety of mainstream idioms for processing SVG, XSL FO, Topic Maps, e-business XML formats, and more. There have always been such offerings on display at conferences, but the increasing proportion and sophistication at XML Europe 2003 was notable.

One of the displays that drew my particular interest showed that DSSSL is still alive and well. Next Solution Co., Ltd. is a Japanese company with several DSSSL-based products for XML publishing. NEXTStylus is a GUI tool for developing DSSSL stylesheets, and NEXTPublisher and DSSSLprint can use DSSSL scripts for print and Internet publishing, offering a variety of advanced formatting features. was demonstrating VisualScript XML, which allows you to use a friendly charting interface to generate structured XML documents. The idea is to provide a user-friendly, drag-and drop template front end in a particular usage domain and to generate XML on the back end. The example demonstrated was an organization chart.

The user drags and drops the role boxes, happily oblivious to the fact that they are editing XML. The tool comes with built in templates and scripts for ebXML, SMIL, and BPML.

Off the show floor, I was treated to an ad-hoc demo of MarrowSoft's Xselerator, a very nifty XSLT IDE for Windows. The demo featured standard IDE functionality, a debugger, and a built-in XPath analyzer.

Jon Bosak on UBL, the Universal Business Language

Simon St. Laurent

Giving XML Europe's opening keynote, Jon Bosak, the "father of XML", confessed that "yes, I have visions". He explained how he hoped XML might help in "saving the world", leveling the playing field of global commerce by lowering the cost of doing business.

Noting that the "social agenda of SGML has always been about creator ownership of content," with vendor, platform, and language neutrality at its core, Bosak now wants to take that social agenda and apply it in a much larger context.

While documents and data are often considered separate territories, he emphasized that the two work together: "Business is built on the concept of standard legally binding documents." Documents are crucial not only as information exchange, but as a key means of keeping humans in the computing loop. Bosak's vision of social change is as much about human business structures as technical ones.

While global integration is a common theme of advertisements for companies selling computer or transportation services, the reality is quite different. Companies (and their intermediaries) which do business globally prefer to use lower-cost EDI transactions, but the initial costs of joining these systems are substantial, keeping out many possible participants. Bridging the gap between the dreams promoted in the advertisements and the reality is difficult, but Bosak sees XML as a key component. Bosak suggests replacing traditional EDI with a multi-layer package, built on standards at all levels:

  • transport -- the Internet
  • a document-centric architecture -- XML
  • royalty-free XML B2B tag set -- UBL
  • royalty-free B2B infrastructure -- ebXML
  • royalty-free office productivity format -- OpenOffice
  • open-source software

He described the combination of open source software and open standards as critical to making this project feasible: "Open source may be the way to get this off the ground, enabling later commercial possibilities."

He also noted several key advantages of ebXML for open source development, particularly its exemption from an IBM patent on electronic trading partner agreements, courtesy of the UN/CEFACT and OASIS involvement in the development process. Combined with the similarly royalty-free Universal Business Language (UBL), a vocabulary for describing business documents, developers can create standard business communications systems without concerns over intellectual property. Some tools, notably freebxml, are already available.

These low-cost systems can then make it possible for small businesses to join global trade networks, benefitting from the attendant cheaper transaction costs without the initial investment of EDI. Bosak hopes that a more open global trading network will mean a more equitable globe, bringing SGML's social values to many more people than ever worked with SGML.

Daniel Veillard looks at XML from an Open Source perspective

Simon St. Laurent

While XML has benefited from free and open source tools since its beginning, the open source and free software community has taken a measured approach to XML. Daniel Veillard gave the XML-centric crowd at XML Europe 2003 a look at XML from a different perspective.

Rather than looking at the tools created by and for the XML community, Veillard stepped back and looked at what the broader open source and free software communities have done with XML. While some of this sounded like the familiar list of XML toolkits and markup-oriented processing, much of it focused instead on how different projects were using XML.

Veillard pointed out that while there are some systems built around the original notion of XML for Web publishing, most of the projects he discussed focused on other XML capabilities. While Veillard's employer (Red Hat) includes over 3600 XML files in its Linux distribution: they serve a wide variety of purposes, largely for configuration.

Veillard noted that XML is becoming the default format for storing application information; after five years, developers now explain why they aren't using XML if they choose another format rather than why they are using it if they do. Tools and easier internationalization are crucial reasons for XML's popularity.

OpenOffice, KOffice, Abiword, and GNUmeric are all using XML-based formats for their files, often compressing it. Veillard noted that they all use different formats at present, but expressed hope for standardization and other interoperability approaches.

On the documentation front, most projects seem to have standardized on the DocBook vocabulary. While a WYSIWYG DocBook editor would be an enormous help, developers are still working with Emacs/PSGML and other tools; and they're building DocBook support into tools like Nautilus, ScrollKeeper, the KDE HelpCenter, and Yelp. KDE's xmlpo and GNOME's intltool help with translation systems.

While acknowledging Java toolkits, Veillard focused on the ready availability of toolkits like expat, his own libxml, QtXML, and the support built into Python and Perl. Developers have focused on the specifications that they need and can understand. Veillard emphasized the cost of sorting out complex or confusing specifications.

Schema validation has been a particularly difficult area, and he expressed hope that RELAX NG might help simplify the process. XML catalogs have already been important for DocBook users and XSLT and XSL-FO processing are also crucial for this group. XSLT is well implemented, while XSL-FO support is growing.

Veillard pointed out some surprising fields where XML had caught on, notably the use of SVG for scalable icons in both GNOME and KDE, with growing library and application support as a result. XML for user interface definition was also important, both in Mozilla's XUL and in GNOME's Glade interface builder. Unlike the commercial XML market, SOAP and XML-RPC web services haven't been taking off rapidly. Veillard mentioned growing Jabber support, however.

He also explored some similarities between the values of open source and free software communities and those of the XML community. Openness and reuse are at the core of both approaches, and data and code reuse can be mutually reinforcing.

Veillard expressed some concerns about XML as well. A DocBook WYSIWYG editor is a major gap and format standardization for applications is just getting started. Developers are also concerned about the dominance of Java and C# in the XML market, as much of their work relies on shared C or C++ libraries.

Veillard concluded by noting that XML's growing complexity may prove a barrier: "Open source developers are good engineers, they only do what they understand."

These reports originally appeared on XMLhack.