Check out this sample run for how the internal data represenation looks like: #pear.
Documentation
Can be found here but is limited at this point. The examples should be very self explanatory IMHO. But don't hesitate to contact me if you have any questions.
I will be happy to receive any suggestions or comments you might have.
Warning
This is under daily development, so don't bother fixing a bug before asking, it might already be fixed in my local tree.