code: func (p *Parser) GenerateCode() *MrbValue {
  	proc := C.mrb_generate_code(p.mrb.state, p.parser)
  	return newValue(p.mrb.state, C.mrb_obj_value(unsafe.Pointer(proc)))
  }
docs: // GenerateCode takes all the internal parser state and generates
  // executable Ruby code, returning the callable proc.