code: func (v *Vec2) Set(s string) error {
  	cur := 0
  	for _, ss := range strings.Split(s, ",") {
  		f, err := strconv.ParseFloat(ss, 32)
  		if err != nil {
  			return fmt.Errorf("error parsing %v, %v", ss, err)
  		}
  		(*v)[cur] = float32(f)
  		cur++
  	}
  	return nil
  }
docs: // Set sets the components of the vector from a string of the form "float,float"