Neal Ford interviews Jay Fields about his new book with Shane Harvie and Martin Fowler, Refactoring: Ruby Edition, why they wrote the book around Ruby and not Dynamic Languages in general, and why he'd take a powerful language over a powerful tool anyday.



Neal Ford: Why choose Ruby as the target and not do a broader book on Refactoring in Dynamic Languages?

Jay Fields: I considered it. The thing is, I've never delivered a production application in any other Dynamic Language. I'm pretty passionate about the opinion that you should only write about things that you've spent real time working with.

It's entirely possible to distill someone else's experiences. Martin Fowler is amazing at capturing knowledge and creating helpful content that will live on outside of one person's mind.

However, Martin Fowler is not the norm. The amount of garbage generated by average programmers making terrible assumptions is appalling. I refuse to be an author who's books are based on speculation. To assume that I could write about refactoring Perl, Python, or any other Dynamic Language without actually doing it would lead to, at best, a waste of the readers time, at worst, I would be to blame for mistakes in production codebases.

I've personally used every refactoring in Refactoring: Ruby Edition. If the refactoring is in the catalog, I've found a context in which I thought it was appropriate. When you read the book, you can count on the fact that what you are reading about has been successful in the past. There's no speculation.

Programming is hard enough when you follow good advise.

Neal: Do you think that the lack of sophisticated tool support discourages people from doing needed refactorings in large code bases?

Jay: Yes. Some people take the leap. When I'm doing Ruby I miss "rename method" and "extract variable" (I use TextMate). But, in general I find that with a more powerful language I miss the refactoring support less. Plus, the interesting refactorings can't be automated anyway. Would a powerful tool be helpful, absolutely, but it's definitely not required.

However, none of that really matters. The people making decisions give Ruby a look and dismiss it because of missing tool support without giving it the time it would take to realize that you don't strictly need a powerful tool if you have a powerful language. It's a shame. But, then again, it gives all of the rubyists an edge.

Neal: Given that you've worked on large scale .NET, Java, and Ruby projects, do Ruby projects tend to end up with less, the same, or more refactorings?

Jay: Ruby projects tend to have far less and much smaller refactorings.

Java and .NET both require you to have strong knowledge of patterns. Patterns are cool and fun to refactor towards and away from. Unfortunately, they are also a sign that we are trapped by our language.

You often run into a roadblock when using Java or .NET and you introduce an elegant pattern to solve the issue. You pat yourself on the back and probably show some team-mates your beautiful implementation. A few weeks later, a corner case breaks the whole thing down. You spend 2 days refactoring away from the previous perfect solution to another, less elegant, but appropriate pattern. It's a lot of "introduce variable", "remove middle man", moving files and deleting files. The result is beautiful... for Java or .NET.

We don't have that in the Ruby world. You solve problems with less code. You metaprogram your way out of repetition, or delegation, or structural duplication. When corner-cases arise, a few tweaks usually do the trick. Which leads back to why tool support isn't strictly required. But, you have to make the leap to experience it.

Neal: What percentage of the refactorings you've identified are different from the original Refactoring book? What do you think drives the differences?

Jay: I like to tell people that 30% of the content is new. It might actually be more. There's not a sentence in the book that hasn't been judged by the authors. The book definitely started out as a code example port, but it's very far from that in it's final form. Stuart Halloway gets credit for pushing us to create new content. I think a port of the original would have been valuable for the Ruby community; however, I'm much more proud of the final product.

Martin and I differ on whether you should bother to read this version if you read the original. Yes, a lot of the content is extremely similar. However, some of the Ruby specific stuff isn't available anywhere else. Several of the refactorings that Shane and I spent months describing were really helpful to us and can save a Rubyist a lot of time. At worst you can skim the information you already know and still get the benefits of reading the new content.

Neal: What is the fastest land animal?

Jay: Me, looking for a drink after a day of discussing process instead of coding.

Neal: Do the powerful features of Ruby (i.e., meta-programming, runtime evaluation, etc.) make it harder to think about refactorings? Do you think that discourages refactoring?

Jay: I think problems are solved differently. When you have more power you tend to create different solutions. Sometimes they are later determined to be "hacks". But, most often the solutions are less code, easier to understand (more straight-forward, less pattern), and perfectly adequate. And, most code with those characteristics doesn't need to be refactored very often.

I don't think it's harder to think about refactorings in Ruby though. In fact, with less code, it's usually more more obvious how things need to change.

Neal: Do you think we'll ever have tools for refactoring as sophisticated as the ones for Java? Why or why not? Does it matter at the end of the day?

Jay: I think there are people who benefit from sophisticated refactoring tools, so I imagine they will be created. But, like I said previously, when your language is powerful, it really doesn't matter at the end of the day. I've been doing a lot of Clojure these days and it's only reinforced this belief. Clojure refactoring support might actually be worse than Ruby, and I still find myself significantly more productive than when I work with Java or .NET.

I'll take a powerful language over a powerful tool anyday.

Neal: Which refactoring that you guys identified surprised you the most?

Jay: It took so long to write the book that I can't remember specific refactorings that surprised me. However, I do remember being surprised by how many additional refactorings we identified. Once we started writing new material additional material kept emerging. I really started thinking that there would be less than 10% of new material. I was definitely wrong, and I'm glad I was.

Neal: Given all the work and innovation you've done for Domain Specific Languages in Ruby, do DSLs lend themselves to refactoring as much as traditional Command/Query APIs?

Jay: That's really a question that requires a lot more context. I'd say in general there's little difference when it comes to refactoring; however, outside factors such as who is using the DSL impact whether it's even possible to refactor a DSL. If you own all the DSL using code, you have freedom. If others rely on the code, a refactoring can be tricky business.

Neal: What is the role of testing for refactoring in Ruby? Do different levels of testing (unit, functional, integration, user acceptance, etc) affect decisions about refactoring? What about newer testing frameworks like RSpec and Cucumber?

Jay: I really don't see any difference in what level of testing I do based upon the language. In Ruby and any other language, Refactoring without tests is a silly idea and an easy way to look like a fool. The Ruby community does tend to have a vibrant testing community; therefore, refactoring is probably more prevalent. However, the unclear view of testing best practices plagues the Ruby community just like everywhere else.

The newer testing frameworks are good for pushing us to the next level of maturity; however, the Ruby community is just as good at failing with the new tools as the Java community is at failing with JUnit. There are contextual testing best practices, but they're so young it's impossible to declare any of them effective widely.

No one has figured out how to test well in any language.

Neal: Do you think that refactoring Rails projects is easier or harder than non-Rails projects? Why?

Jay: I think the only Ruby work I ever did was with Rails, so I won't bother to speculate. (I'm sticking to my stance from my first answer.)

Thanks for taking the time Neal. It's always a pleasure.