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Eloquent Ruby: An Interview with Russ Olsen

Pat Eyler interviews Russ Olsen about his new book, Eloquent Ruby, recommended programming practices, why it's beneficial to learn a new programming language, and why it's sometimes worthwhile to color outside the lines.
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Russ Olsen (@russolsen) has just written Eloquent Ruby, which is already receiving praise from many in the Ruby Community. Since we don't normally think about programming eloquently, Russel and I took a bit of time to talk about what it means and how to do it. Enjoy!

You can also read an earlier interview with Russ, or my review of his earlier book Design Patters in Ruby.

Pat Eyler: Why Eloquent Ruby?

Russ Olsen: Eloquent Ruby grew out of my experiences trying to bring programmers new to Ruby up to speed on the language. It turns out that this is both very easy and very hard, in that order. The easy part is to teach the basics of the language. On one level Ruby is a very straightforward object oriented programming language. There classes and methods and instance variables and all the rest, and if you are a Java or C# programmer you can pick up those parts of Ruby in short order. Surprisingly, figuring out the more exotic aspects of the language is not that much more difficult. If you are a Java or C# programmer, then dynamic typing, code blocks and monkey patching will seem strange, but it's amazing how quickly most people grasp these ideas.

It's after they have the basics down that the hard part begins, usually in the form of some very pointed questions: What possible advantage is there to dynamic typing? What is a code block good for? Why would you ever want to change a class definition? Method_missing? Really? The questions are Ruby specific, but the problem is as old as the first programming language: There is a world of difference between knowing about a programming language and being able to use it the way it is meant to be used. The idea behind Eloquent Ruby is to speed people through that "I know the grammar but I kind of don't get it" no-man's land. In the book I talk about how Ruby programmers really use the language and why we do it that way.

Pat: What does it mean to program eloquently?

Russ: It means making the best use of your programming language. If you think about it, programs have two different functions: On the one hand they are mechanisms, little intellectual gears and widgets that do things when you feed them into a computer. But programs are also meant to be read by humans; maybe by the author this week, possibly by another programmer next week and conceivably by the 43rd poor soul who comes along in a few years. An eloquent program does both jobs well: It functions correctly and with a minimum of fuss, while at the same time communicating how it does its thing to the people who need to maintain it.

Pat: Learning another language makes us better speakers of our own languages. How does learning another programming language help us program better in our current language?

Russ: Every programming language is, in some sense, a fresh answer to the question, "How do you write code?" I think learning a new programming language is an exercise in starting over, in taking a fresh look at what's important and what's not. Programmers are people, and we tend to acquire habits; we do things a certain way just because that's the way we do them.

Learning a new programming language is a great way to break out of your habits. On the one hand, when you learn a new language, you will be spending at least some time way outside of your comfort zone; all by itself that tends to shock you out of your daily programming routine. On the other hand, learning a new programming language tends to get you talking to or reading new people, people who will look at the programming world a different way. As someone who has spent the past few years doing mostly Ruby and a little bit of Java, I know that the Ruby experience has changed the way that I do Java.

Pat: Eloquent speakers tend to be well read. How does code reading impact eloquent programing?

Russ: Reading other people's code is one of the keys to picking up a new programming language. If you think about it, no one learns English or Chinese by simply reading a book about English or Chinese and going off to invent their own sentences. A key part of learning a new spoken language is to talk to and read native speakers. In the same way, since every programming language is part technology and part culture, knowing how the language works is key, but knowing how people really use it is important too. For example, when they first stumble over method_missing, most new Ruby programmers assume that it's some kind of obscure error handling facility. You really have to go out and see what people are doing with method_missing to understand just how powerful being able to respond to calls to non-existent methods is.

How do you go about learning from other people's code? I wouldn't just sit down with a great mound of code and start reading. Instead I would start with a problem, with some code that needs to be written. Then go off into the Ruby standard library or into Rails or some other well respected source and try to find out how they have solved the same sort of problem. Personally, I like the "peek at the answer" approach. Take a look at how someone else has done it, get the general idea and then put the other guy's work away and try to do it yourself. If you get stuck, you can always check back to see where you went wrong. Best practices are all well and good, but the best best practice is to think for yourself.

Pat: Another factor in becoming an eloquent speaker is to spend time speaking. Code katas seem to be an approach to doing this with programming. What kinds of programming practice do you recommend?

Russ: When I was in college I had a part time job in the Dean's office. One of the things they would have me do every semester was to compile statistics on the student body, which in those days we did by hand. So I would spend an afternoon sorting through this huge pile of student records, averaging SAT scores and GPAs.

It was boring, but it was also interesting, because I could see a lot about the personal backgrounds of my fellow students, things that the average civilian wouldn't know about. The thing that struck me was that every one of the students was different. Some of them played the cello and some played baseball. Some were clearly very well off and some were from places that I wouldn't think of going into at night. And these were all people who were going to the same school, studying more or less the same thing.

That's a long way of saying that I don't think there is a single answer to the question of "how do you do it?" For example, I love Dave Thomas' idea of code kata and I'm really glad he put the time in getting it started. But it wouldn't work for me—I just have never done well with even the minimal structure that the katas provide. My favorite way to learn a new programming language is to think of some impossible task—build a whole database management system complete with SQL or something equally wild—and just give it a shot. I pretty much have a 100% failure rate with these projects, but the value is in what I learn as I fail.

But maybe the kata thing works for you—it certainly seems to work for a lot of people. So do that. Or do something else. It doesn't much matter what exactly you do—it's the doing that matters.

Pat: Finally, if you could recommend one practice to programmers, what would it be and why?

Russ: Actually I have two bits of advice: The first is follow the rules. Every programming community has a set of best practices, ways of doing things that have been hammered out through experience. You need to pay attention to those rules, especially when you are new, just learning. Mostly you want to color between the lines, because the lines were put there for good reasons.

But you also want to understand the why behind the rules. I tried to do that in Eloquent Ruby as much as I could, to the point of explaining why Ruby programmers indent with two spaces. Don't just take the rules as handed down from above; get inside of them, figure out why they are there.

Which brings me to my second bit of advice: Don't be afraid to break the rules. Like the pirate code, programming best practices are more a set of guidelines. If you know the rules and you know the why behind the rules, then every now and then you can color outside of the lines, confident that you are doing it for a good reason.

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