Refactor for more agile development

There is wide support for separating the question bank from quiz taking but there hasn't been any progress in the code yet. That's because it's quite complicated and will require consensus on how to proceed. The Quiz module in its original design was not intended to have LMS features but has slowly evolved that way over time. Unfortunately, the original structure can bend only so far.

I propose that with Quiz 4.x we allow a blank slate for the design of the data and object structures. mbutcher's refactoring of the question types into OO has been great. Let's do that sort of treatment on the whole module. If you were to write the quiz module today, how would you do it differently? Well, we can do that.

Backward compatibility is an important concern. Because there are interchange formats for quiz and question data, we can achieve that by having a robust import and export system, which we want anyway. So even if the DB changes in incompatible ways between 3.x and 4.x, the upgrade path can be simple: 1) Export all quizzes from 3.x; 2) uninstall 3.x; 3) install 4.x; 4) reimport.

The QTI (Question Test Interoperability) spec from IMS provides a good model for quiz entities and actors:
http://www.imsglobal.org/question/qtiv2p1pd2/imsqti_oviewv2p1pd2.html

They also have a page we can use to ground/define the terms:
http://www.imsglobal.org/question/qtiv2p1pd2/imsqti_infov2p1pd2.html#ter...

Adopting the QTI model should allow the module to parse and store all the data from imports from any format, even if the Drupal Quiz module can't make use of them. More importantly, it provides a flexible structure for implementing these other features over time without resorting to big changes.

What do people think of this? What are ways to go about it?

One way to go about it is to start pulling the question item definitions and banking out of Quiz and let Quiz focus on the Interactive Assessment and Reporting functionality. There might then be an Assessment Item Bank module that the Quiz module depends on. Alternately, Quiz could become the storage area and a new module Interactive Assessment or something could pull out the features that define instances of use of quizzes.

This will probably be a long conversation. I hope this issue ticket serves to help organize it.