Friday, May 18, 2007

Appealing talks for me at XML Prague 2007

XML Prague 2007 will take place in June 16th and 17th.
From the published program I found special interest in:

Generative XPath
Oleg Paraschenko
Saint-Petersburg State University

The most convenient approach to navigate over XML trees is to use XPath queries. But there is no reason to limit ourselves to XML only. Indeed, it's useful to have XPath for navigating over arbitrary tree-like structures. There are a number of projects, in which developers have tried to implement XPath over project-specific hierarchical data. Unfortunately, most of these attempts resulted in something that resembled XPath, but was not XPath. The problem is that implementing XPath, even version 1.0, is a difficult task. We propose an alternative approach. Generative XPath is an XPath 1.0 processor that can be adapted to different hierarchical memory structures and different programming languages. Customizing Generative XPath to a specific environment is several magnitudes of order easier than implementing XPath from scratch.

The Generative XPath framework consists of three components:

  • XPath compiler,
  • XML virtual machine,
  • native (customization) layer.

The XPath compiler transforms XPath expressions to an executable code for the virtual machine. During execution, the code interacts with the native layer to access the tree nodes and its properties.

This paper explains what the virtual machine is, what is expected from the customization layer, and how they work together. Also, background information about the design and implementation of Generative XPath is given.

XML Processing by Streaming
Mohamed Zergaoui

The first part will be to present the state of the art of XML Streaming processing by reviewing the products in place (joost, cocoon, saxon, etc.), the API available (SAX, Stax, XOM), languages (CDuce, XDuce, XJ), and the spec in progress or stalled (STX, XML Processing, XQuery update). Speaking of what is currently in preparation (i.e. an XML Streaming XG at W3C). And taking the time to present what has already been done in SGML time (Balise and Omnimark, cursor idea that can be find in Arbortext OID in ACL, etc.)

Then the goal is to present all the area where some work has still to be done and give some hints on an elaborated vision of XML Processing trough different kind of process : around constraints, normalizing, streamable path, multilayer transformation, and last but not least constraints aware streamable path. Some light will be spot on static analysis of XSLT and XQuery to detect streamable instances. What are the needed evolutions of the cursor model? What are XDuce-like languages added values?

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