This example demands that you understand some domain-specific needs (of a text editor), so it's a little annoying. But, the main idea is right on the mark. Th

This example demands that you understand some domain-specific needs (of a text editor), so it's a little annoying. But, the main idea is right on the mark. The point is that the natural structure of the code (that uses closures) is completely impossible to achieve without closures. Great stuff! I think the author gets it. :-)