The exporter now uses the new ID Property mechanism of Blender to store most of the YafaRay specific settings, which greatly helps to add custom properties to objects, materials etc. without adding any custom code to other Blender parts. This is probably a big step forward for the integration of many external renderers.
The Python export scripts for Blender can be checked out with:
svn co https://ssl.little-isp.de/svn/lynx/yafaray/blender/python
These scripts obviously need to go into Blender's scripts directory. For the scripts to work you also need to copy the python bindings to Blender's scripts directory.
When the scripts are copied to your scripts folder you can access the generic "ID Property Browser" via the Help menu.
One important point is export of Blender texture system. Currently the new materials are all node based. There is little point in giving them lots of Blender specific options again when the fundamental differences, such as physical properties they need to be comply with, force more specialized materials with different appearance and behaviour anyway.
Instead there has been intended a special type of node that allows to resemble the texture layers in Blender while still allowing flexible assignment to the specific node inputs a given material features. As a little bonus, there is technically no reason to have the same layer stack for each input. As drawback, the number of nodes can become quite high when using many channels in many layers. And inevitably, some of the Blender channels will be unused or mapped to properties that only roughly compare to those of the Blender material.
The translation of the layer stack to nodes looks like this: