Would it be possible to use this with THREE.Vector3?

Sorry if I'm being daft, but would this work with passing a three.vector in as a variable, and allowing the code to call methods on that? I want to allow declarative animations in @scenevr.

```
var src = 'v.multiplyScalar(t)';
var ast = parse(src).body[0].expression;

console.log(evaluate(ast, {
v: new THREE.Vector3,
t : new Date().valueOf()
}));
```