I'm trying to get familiar with constraint programming.
All documentation/videos I've seen so far just contain description of top-level concepts and code examples based on CP-libraries utilization (like Choko, Gecode, JaCoP etc).
I'd like to implement at least something simple in Java without any libraries.
Are there any resources where I can find working code in Java/C#/C++/Python which implements main CP ideas? (at least "send more money" problem solution).
(or, maybe, if somebody can explain it here, it would be great).