Imperative to OO to Functional
This screencast demonstrates a refactoring through three and a half paradigms. First, we see the code in imperative form: code that mutates data, with the code and data being separated. Then we merge some of the data and code to form an object to get object oriented code: code and data mixed, with mutation. We quickly look at a variant of this where the object is only allowed to have pure functions (no mutation or IO). Finally, we remove the object, leaving only the functions, which gives us a more standard functional solution.