Grinding through mal-js implementation, can't decide between using js objects or a bunch of classes.

JS doesn't have 'symbol' or 'keyword' separate from string, or 'vector' different from array, but I can add a type property for the times when things are different.

Writing my own types is theoretically safer, since mal code won't be calling js methods directly there's less surface area for naughy code to fall through.

Dunno. Going to sleep on it.