ppmacros can wrap - how do we know to pass them back down?

 with #define X we can know because of '#' .. maybe make read_input keep a context stack, and offer input to top of stack, get stack location back when input is accepted and push on stack if different?

 ahh, that could be nice, that allows a func( y ) to be conditionally accepted .. and if the ; is on the next line the element parses it, else if it is a { then it opens a new frame.

 how do we pass args to the vm?
 just C functions, I guess?

 vm_libpath


 ok, so when we close a library or builtin, we push it to the next level.
 root does following ->