Over the past year I've been thinking about how to make my own language. It's a pretty big undertaking and I've been too busy with other projects to put any serious effort into it, so I just think about it when I go for a walk. Mostly I try to convince myself to not make a language but it sounds like a lot of fun. With the explosion of JavaScript, and so few people wanting to write JavaScript, it seems like other people think writing a language sounds like fun too. We have CoffeeScript, IcedCoffeeScript, Roy, JSX, Amber, Dart, and many others. And that's just a list of recent languages that compile to JavaScript. Many more languages have come out, relatively recently, such as Go, Fancy, Elixir and Loop. Most of these languages will be minor dents in the history of programming languages, but that is OK. Not everything has to be important to be worth doing. But they have gotten me thinking. Should I create a language? What would it have to offer? Is the effort worth it? Below are thoughts that have steered my decision process for when I get some time to start hacking on a language. The thoughts are targeted at me, someone who has little experience building a language, not a professional.
Wednesday, June 6, 2012
Thursday, May 17, 2012
Phantom type examples in Ocaml
What are phantom types
Phantom types are a way for multiple types to have the same exact underlying representation but still be seen as a distinct type by the compiler. The common example is units of measurements. Feet and meters are both distances and are best represented as an int or float, but it makes no sense to add a foot to a meter. Phantom types allow you to solve this and still represent a foot and a meter exactly the same. One can think of this as the opposite of duck typing. In duck typing, if you only care if the current value you are working with has four legs, a cat a dog and a table are the effectively the same thing. In phantom types you care about what something actually represents and that means they are different, even though underneath they are represented with the same type.