Version 1.0.5 is the first that includes all the classes 100% coverage.
Although that definitely does not mean the library has no bugs, it certainly will help very much in making it stay very stable.
The current version supports variables, @extend, user functions (albeit not the @return yet), and nested rules and attributes.
Previous versions had definite bugs that got fixed as I was writing the full coverage tests. If you have any problem with the library or csspp command line tool, let me know by posting a ticket here. Note that patches are more than welcome!
Thank you.
Alexis