Weird technical issues are dealt with. It turns out I was actually really close to getting the first interesting test to pass; I just needed to tweak the default display of floating point numbers.
Now, the next test works with variables, which I haven't really handled at all. Doing this requires a surprising amount of stuff. Variable initialization is handled by diverting to "global decl", so I'm going to need to handle that. Once I get that working, it'll hit the variable assignments, and I'll have to implement those... which means actually storing the variables. Hopefully, after that, it'll just kind of go, but it's quite hard to say.
Once this is in a workable state, I think it'd be very interesting to port it to other languages, because I believe the way I'm writing it is relatively language-agnostic. But, I can't do that soon, and I shouldn't do anything else tonight, because it's late.