I don't think that a Schwartzian Transform module really makes sense. It's a simple technique. Trying to modularize it wouldn't effectively abstract anything because the hard part, the transformations themselves, are completely dependent on the data being sorted.

In fact, you would likely code yourself into a corner if you tried to modularize the ST. In your suggestion, for instance, your Sort::Schwartzian object takes an "op" argument. That suggests that it wouldn't be easy to sort on two different fields with your module.

-sauoq
"My two cents aren't worth a dime.";