The Io Programming Language
Yes, I’m having a go-round with Seven Languages in Seven Weeks—in my copious free time not devoted to work or my Objective-C kung-fu—and I’ve begun with Io, a little prototype-based language by Steve DeKorte.
I’m something of a javascript expert; in fact, of all the people I know, I’m the only person that actively likes the language. More bluntly: I think I’m the only person I know who doesn’t hate using it.
So: Io. Io is like a clean, pure message-passing version of javascript, sans-DOM. Sans much of anything, really: it’s very lightweight and has some really neat lisp-y features and a mega-simple Coroutine/Agent system, but it has almost no syntactic sugar. The Io Guide is pretty good; but the community seems small and good reference material is hard to come by. Io is also kinda hard to google for. If you do google it, you’ll often find blog posts about the very book I’m using.
Enough rambling! Let’s see some code! Actually, let’s start with the install. It’s hosted on GitHub, so:
- git clone http://github.com/stevedekorte/io.git
- make vm
- sudo make port
- make <name_of_addon_you_want_here>
- sudo make install
And you’ll find yourself with the io command line utility. Many of the port packages (and therefore Io AddOns) wouldn’t compile for me, and I ran out of patience trying to debug. Sadly, these included Yajl, which is a kickass streaming JSON parser and builder. I recommend that you at least `make Socket`, and if you’re a web programmer, `make Volcano` as well. If you want to add the AddOn later, head back to your Io source folder, “make <addon name>” and “sudo make install” again. This has made be appreciate how awesome and blessed the Ruby community is with rubygems and rip.
Typing “io” will get you an interpreter terminal, so it’s easy to have a play. Here’s some sample code:
There’s lots more to it, of course. You get a really super-clean implementation of everything that is awesome about prototypal inheritance. Here’s a basic twitter frontend, to demonstrate how easy building a simple HTTP server can be:
You’ll need Socket and Volcano, I think. There is a Twitter AddOn, but it requires Yajl (reasonable), which I can’t build on either of my Macs.
You can send any message asynchronously by prefixing it with “@”. On line 19 of the twitter thing I send @fetch asynchronously and assign the result to “twits”: this creates a “future”—basically, a placeholder. Only when you check the value of this placeholder does it block waiting for @fetch to complete. It’s pretty cool to have this kind of non-blocking method invocation baked in. It’s a bit like Node.js, another one of my favorite shiny new toys.
I like Io; at least, I like where it is going. I’m not sure that it would replace anything that I currently use, however it did make me focus and clarify my thinking about where I think javascript should go.
Oh, and I put my de-fucko’d sample code up on GitHub here.
