I just put the finishing touches on a tiny little interpreter project: Jasic. Jasic is a dialect of the original BASIC programming language. It lacks functions and scope, but it’s a usable language. Even on an old Apple IIe, it was powerful enough to get me hooked on coding for life. Also, you can draw a Mandelbrot set with it.

I wanted to see if I could fit a complete interpreter in a single readable Java file. It worked out better than expected, so I went ahead and cleaned up the code and commented the hell out of it. If you’ve always wanted to learn more about interpreters, now you’ve got a little primer.

Here’s a little code to give you a flavor of the language:

' initialize the loop counter count = 10 ' stop looping if we're done top: if count = 0 then end print "Hello, world!" ' decrement and restart the loop count = count - 1 goto top end:

Old school! All of the code is right here in Jasic.java. There’s also a README to help get you started. What are you waiting for?