That's pretty neat. Clearly some level of parsing needs to happen before run time, or else it couldn't even balance braces to know where the function body ends.

That's pretty neat. Clearly some level of parsing needs to happen before run time, or else it couldn't even balance braces to know where the function body ends. So it must be that it parses the function body just enough to figure out where it starts and ends, then does a complete parse at runtime (probably building off the results from the first stage).