Apprenticeship Month One Report

Apprenticeship Month One Report

Paul Pagel
Paul Pagel
June 30, 2008

8th Light has an apprenticeship program whereby an 8th Light craftsman will mentor an individual for three months.

During that time, the craftsperson becomes responsible for a single apprentice. I am one month into a mentorship with an apprentice. This blog is about observations I have made about myself as a mentor.


My apprentice asks me questions that I wouldn’t ask myself. I had him do an exercise about Law of Demeter, to find Law of Demeter violations in my code base. He found something like:

1Law of Demeter
3“Ted Williams”.to_s.strip.upcase

He was counting the periods, which is what I explained is often good measurement of Law of Demeter violations. Yet this is not a Law of Demeter violation. Each one of those methods returns itself (a string) in a changed state. It is not a string of implementation details- this example is just changing a single object.

The pivotal piece of information is that all of these methods on string return the string itself. Also, is anything inside of Ruby core language capable of Law of Demeter? It is unlikely to change, and is there a problem being coupled tightly to your language?

I sometimes get desensitized to the original premises of good development. When I first learn something, I remember the example of the rule more than the value of the rule. The value of learning about Demeter is rooted in encapsulating logic in such a way to hide implementations from an object’s clients.

When I first learned about Demeter, all I could do was point out violations. The more I developed, the more it was internalized as a guide for a higher development idea. I want to keep my modules decoupled.

However, that notion only came with development experience. Now I don’t think in terms of violations or non-violations of Demeter when I read a piece of code. It is just ingrained in my developmental context that I should develop my modules in such a way that they are autonomous.

This weeds out most Law of Demeter violations by itself. Bringing these premises back up in my development as a craftsman gets my curiosity started. Like a good song or piece of writing, every time I come back to it, I take something different from it.


Sometimes I forget how important teaching is to the craftsmanship model, because I am still an extreme novice at it. It‘s one of the steps involved with internalizing development skills. When I pair with my mentor, I am constantly amazed at how he skips steps in process.

Instead of following a linear thought pattern to a solution, it seems there is a giant shortcut in the rational processes I go through. That gap is a lookup table of solutions in his head. It appears so easy and effortless. Teaching is part of a formula that has given him a development context that is superior to mine.

The more I teach, the more I internalize the ideas about development.

There is a baseball story from about a year ago. Greg Maddux was warming up before a game and his catcher exclaimed to the pitching coach, “I bet I could catch him with my eyes closed.” Well, after much effort, they convinced Maddux to give it a shot.

The catcher was going to call his pitch, then close his eyes. When the ball was about to hit his mitt, the pitching coach with his eyes open was going to yell “now”, whereupon the catcher would squeeze his glove on the ball. Well, on the third try, the catcher caught the ball.

The degree of difficulty of the exercise is incredible, but Greg Maddux had spent so many years internalizing the mechanics of his craft that he could effortlessly hit the catcher’s mitt. There probably are only a few pitchers in the long history of baseball who could match that exercise.

I am not anywhere near that kind of skill in development, but that is my goal. When you get the mechanics of your craft to be intuition, it frees your mind to think about and solve larger problems. I have been fortunate to spend time with enough great developers to see this mastery in action.


For me, what is special about teaching is the commitment of thoughts to sound. Forcing something outside of my internal monologue always changes it, even if it is a small change.

When I explain something, I often have to explain it multiple ways (this is telling of my communication skills, not of my apprentice’s learning skills).

So, the more I am forced to answer questions on the spot, the better I get at quickly thinking through a question and giving a good answer. This dialogue is another one of the mental exercises which translates into my everyday development.

It makes me a better pair programmer, better presenter, and better writer. Being able to accurately explain a problem and a solution using the language of software development is a very important tool in being a successful craftsman, and a tool that I fight uphill to improve upon.

When I go to a talk at a conference and the presenter hits the problem and solution perfectly, it is a wonderful experience. The same is true when a team member can explain a solution in such intuitive terms that everyone gets it immediately.

Apprenticeship for me is as much about internalizing and expanding my own skill set as it is about expanding my apprentice’s.