Last year at FOSCON (and the next day at OSCON), _why showed the first animated installments of his “Least Surprised” cartoons, to the delight of all present. In one of them, Time.now.is_a? MagicTime, Malsky asked his audience to imagine what Ruby will be like in three years. The first suggestion? “Maybe we’ll have our own virtual machine by then.” Malsky was appalled. “No, no! Come on, guys! Three years? Ruby will have ten virtual machines built inside every metaclass by then. Be creative!”

For several of us sitting in the back, “ten virtual machines built inside every metaclass” was one of the biggest laugh lines of the evening.

Of course, it’s still absurd—but maybe only by two or three orders of magnitude instead of four. I’m amazed at what’s happening in the world of Ruby and high-performance virtual machines. I’m personally aware of seven (!) projects to either build a Ruby VM or implement Ruby on an existing VM:

  • Of course, there’s YARV.

  • JRuby, which has been around for a long time as a Ruby interpreter, is starting to become a true bytecode compiler in the Jython style.
  • There are no less than three projects to implement Ruby on the .Net CLR, building on the lessons of IronPython.
  • The Cardinal project, to implement Ruby on Parrot, has been restarted by Kevin Tew. (And Parrot itself is making serious progress again, after some difficulties.)
  • Finally, there’s a project underway to implement Ruby on Nicolas Cannasse’s Neko VM.

Naturally, there’ll be some winnowing of these options over time. But it seems clear that the Ruby community will end up with at least three solid VM options: YARV, JRuby and some variety of Ruby on the CLR. The core Ruby developers are strongly committed to YARV. The CLR version is too important not to do (and to my mind, last week’s announcement of IronPython 1.0, still as an open source project, makes a mature Ruby implementation on the CLR even more likely). And of course, Sun has now hired the two main JRuby developers, throwing at least some of their weight behind that project.

Come on, guys! Three years? Ruby will have three virtual machines that’ll run in every kind of IT environment by then. Be creative!

(And there is still room for serious creativity there. I’ll write more about that soon.)