Perhaps a better example than this to illustrate the API?

Sure, I can do that.

Wouldn't it be better to have the order not be a concern of the sorter? i.e. this function would just return weather two items are equal, less than or greater than, but which direction the sort operates is the responsibility of the library code?

Hmm, I'm not sure. I need to be able to handle ascending or descending when the column is clicked multiple times. I will think about it more.