Thanks for the feedback.

The chronic project was actually the original motivation behind natty. I think the chronic project is great, but I believe the grammar-based, AST approach is the way to go for long-term maintainability.

Implementing relative times has been on my list of things to do (in addition to recurrence.) I created a feature request here: http://github.com/joestelmach/natty/issues#issue/4, so feel free to list any time formats you'd like to see implemented.

I agree that a generic list of test cases would be nice. Any thoughts on how such a list should be published?