I have been involved in several discussions about programming languages lately and people have assumed that since I spend lots of time in the Ruby world and with dynamic languages in general I don’t like static typing. Many people in the dynamic language communities definitely expresses opinions that sound like they dislike static typing quite a lot.

I’m trying to not sound defensive here, but I feel the need to clarify my position on the whole discussion. Partly because I think that people are being extremely dogmatic and short-sighted by having an attitude like that.

Most of my time I spend coding in Java and in Ruby. My personal preference are to languages such as Common Lisp and Io, but there is no real chance to use them in my day-to-day work. Ruby neatly fits the purpose of a dynamic language that is close to Lisp for my taste. And I’m involved in JRuby because I believe that there is great worth in the Java platform, but also that many Java programmers would benefit from staying less in the Java language.

I have done my time with Haskell, ML, Scala and several other quite statically typed languages. In general, the fact that I don’t speak that much about those languages is that I have less exposure to them in my day-to-day life.

But this is the thing. I don’t dislike static typing. Absolutely not. It’s extremely useful. In many circumstances it gives me things that really can’t have in a dynamic language.

Interesting thought: Smalltalk is generally called a dynamic language with very late binding. There are no static type tags and no type inference happening. The only type checking that happens will happen at runtime. In this regard, Smalltalk is exactly like Ruby. The main difference is that when you’re working with Smalltalk, it is _always_ runtime. Because of the image based system, the type checking actually happens when you do the programming. There is no real difference between coding time and runtime. Interestingly, this means that Smalltalk tools and environments have most of the same features as a static programming language, while still being dynamic. So a runtime based image system in a dynamic, late bound programming language will actually give you many of the benefits of static typing at compile time.

So the main take away is that I really believe that static typing is extremely important. It’s very, very useful, but not in all circumstances. The fact that we reach for a statically typed programming language by default is something we really need to work with though, because it’s not always the right choice. I’m going to say this in even stronger words. In most cases a statically typed language is a premature optimization that gets extremely much in the way of productivity. That doesn’t mean you shouldn’t choose a statically typed language when it’s the best solution for the problem. But this should be a conscious choice and not by fiat, just because Java is one of the dominant languages right now. And if you need a statically typed language, make sure that you choose one that doesn’t revel in unnecessary type tags. (Java, C#, C++, I’m looking at you.) My current choice for a static language is Scala – it strikes a good balance in most cases.

A statically typed language with type inference will give you some of the same benefits as a good dynamic language, but definitely not all of them. In particular, you get different benefits and a larger degree of flexibility from a dynamic language that can’t be achieved in a static language. Neal Ford and others have been talking about the distinction between dynamic and static typing as being incorrect. The real question is between essence and ceremony. Java is a ceremonious language because it needs you to do several dances to the rain gods to declare even the simplest form of method. In an essential language you will say what you need to say, but nothing else. This is one of the reasons dynamic languages and type inferenced static languages sometimes look quite alike – it’s the absence of ceremony that people react to. That doesn’t mean any essential language can be replaced by another. And with regads to ceremony – don’t use a ceremonious language at all. Please. There is no reason and there are many alternatives that are better.

My three level architecture of layers should probably be updated to say that the stable layer should be an essential, statically typed language. The soft/dynamic layer should almost always be a strongly typed dynamic essential language, and the DSL layers stays the same.

Basically, I believe that you should be extremely pragmatic with regards to both static and dynamic typing. They are tools that solve different problems. But out industry today have a tendency to be very dogmatic about these issues, and that’s the real danger I think. I’m happy to see language-oriented programming and polyglot programming get more traction, because they improve a programmers pragmatic sensibilities.

20 Comments | By Ola Bini | In: Uncategorized | tags: haskell, ruby, scala, static typing. | #

This post is a bit of a follow up to my rant about Unit testing in Scala two days back. First let me tell you that that story actually has a happy ending. Eric Torreborne (creator of the Specs framework) immediately stepped up and helped me, and the problem seemed to be a lack of support for JUnit4 test running, which he subsequently implemented. I’m going to reintegrate
specs into my test suite later today. So that makes me happy. I might still retain JtestR. Actually, it would be a bit interesting to see the differences in writing tests in Ruby and Scala.

I spent some time on #scala on FreeNode yesterday. Overall it was an interesting experience. We ended up talking a bit about the unit testing bit, and Ant integration in particular. I’ll get back to that conversation later. But this sparked in me the question why I felt that it was really important to have Ant integration. Does it actually matter?

I have kind of assumed that for a tool running on the JVM, that people might need during their build process, integration with Ant and Maven is more or less a must. It doesn’t really matter what I think of these tools. If I want anyone to actually use the tool in question, this needs to work. In many cases that means it’s not enough to just have a Java class that can be called with the Java-task in Ant. The integration part is a quite small step, but important enough. Or at least I think it is.

I am thinking that no matter what you think of Ant, it’s one of those established tools that are here to stay for a long time. I know that I reach for Ant by default when I need something built. I know there are technologically better choices out there. Being a Ruby person, I know that Rake is totally superior, and that there is Raven and Buildr who both provide lots of support for building my project with Ruby. So why do I still reach for Ant whenever I start a new project?

I guess one of the reasons is that I’m almost always building open source projects. I want people to use my stuff, to do things with it. That means the barrier to entry need to be as low as possible. For Java, the de facto standard build system is still Ant, so the chance of people having it installed is good. Ant is easy enough to work with. Sure, it can be painful for larger things, but for smaller projects there really is no problem with Ant.

What do you think? Does it matter if you use established tools, that might be technologically inferior? Or should you always go for the best solution?

Sometimes I’m considering using other tools for build my own personal projects, but I never know enough to say with certainty I will never release it. That means I have two choices – either I use something else first and then convert it if I release it, or I just go with Ant directly.

Now, heading back to that conversation. It started with a comment about “an ant task for failing unit tests is severely overrated”. Then it went rapidly downhill to “Haskell shits all over Ant for a build script for example”, at which point I totally tuned out. Haskell might be extremely well suited for build scripts, but it’s not an established tool that anyone can use from their tool chain. And further, I got two examples of how these build scripts would look, later in the conversation, and both of them were barely better than shell scripts for building and testing. Now there is a very good reason people aren’t using shell scripts for their standard building and testing tool chain.

Or am I being totally unreasonable about this? (Note, I haven’t in any way defended the technological superiority of Ant in this post, just to make it clear.)

5 Comments | By Ola Bini | In: Uncategorized | tags: ant, build, haskell, scala. | #