code: func (s *scope) makevar(varname string) string {
  	s.n++
  	var genName = varname + strconv.Itoa(s.n)
  	s.stack[len(s.stack)-1][varname] = genName
  	return genName
  }
docs: // makevar generates and returns a new JS name for the given variable name, adds
  // that mapping to this scope.