Driver Interface and protected properties

Hi all, I am currently working on the SDG (renderer) driver interface refactoring (bug #5859). In SDG, users are allowed and encouraged to write their own specific drivers. That means : drivers are user-space code. In the new design, a base class calls a set of methods that drivers expose (the interface). All drivers are descendent of this base class. The base class also contains : - a very few protected methods that drivers may call for options setup, etc... - a bunch of protected properties that drivers read data and informations from Because drivers are considered user-space code, I am worried about these properties : do you think that all interactions between the base class and drivers should be method-based, and all properties made private ? Regards -- og