Thanksgiving, Reuse, and Slack

In Leftovers, Dan "Superman" Steinberg brings up the question of how to deal with reuse in this age of agile, lean development.

One trick is to just have a really good memory. Alas, given that most of us are human, that doesn't seem to work too well in practice. :-) Given that we're tool users and creators, we do have some options in helping us remember. A classic is a catalog of index cards -- the post-modern equivalent: a big junkyard of code (and you do, of course, keep *all* of your code in a repository, right?) and a local search engine. Another trick is creating and using an orphaned code wiki -- i.e., if the code is something interesting enough to save, add it to a wiki.

Dan asked "With coding - how do we think of reuse? Are we at a point where we start planning for our code leftovers? XP teaches us not to code for situations we don't yet need, but a customer could have a reusability story." Basically, the question is where does "reuse" fit in with the core computer science notions of necessary and sufficient? IMHO, the missing key is the notion of slack. Is there enough slack in the system to allow it to function reliably and robustly in the face of change? Most developers are exposed to this notion in practice in dealing with performance but slack is crucial in all aspects of software. To continue with Dan's food analogy, the orphaned code wiki, for example, is akin to putting leftovers in the freezer.

Big thanks to Dan for his tireless efforts in making the world a better place.