Many changes for Config4GNU

Config4GNU, a project to provide a single unified interface to system configuration data on Linux computer systems, is still quite active. A lot has happened since the last news update, including the writing of a new implementation guide, using a new XML library, and finding a new way to do scripting language bindings.

In late November, all of December, and even some of January, a lot of work has been focused on an "implementation" document, which is a guide for how various parts of the system will work and how they fit together. It is a more detailed document than anything we have done so far. Understand that it is a constant work-in-progress; there are many parts that are out of place, inconsistent, or already out-of-date as the project changes. It can be viewed at http://config4gnu.sourceforge.net/docs/implementation/.

In addition, out of an interest in using an XML parser that supported XML schema, we switched to the Xerces XML parser, available at http://xml.apache.org. It is written in C++, which required us to rewrite the client in C++. This turned out to be a great improvement. Both Justin and I have found that writing the code in C++ is easier to read and to create new things.

Finally, only recently we came across SWIG (http://www.swig.org), which is a program that automatically generates bindings for many scripting languages, including Perl and PHP. Using SWIG as part of the build process allows us to easily keep the Perl and PHP bindings always up-to-date.