func (v *Vec) Set(s string) error {
	if _, err := fmt.Sscanf(s, "(%f,%f)", &v.X, &v.Y); err != nil {
		return fmt.Errorf("invalid syntax \"%s\"", s)
	}
	return nil
}
func (v *Vec) Set(s string) error {
	if _, err := fmt.Sscanf(s, "(%f,%f)", &v.X, &v.Y); err != nil {
		return fmt.Errorf("invalid syntax \"%s\"", s)
	}
	return nil
}
func ( v * Vec ) Set ( s string ) error { if _ , err := fmt . Sscanf ( s , " " , & v . X , & v . Y ) ; err != nil { return fmt . Errorf ( " \" \" " , s ) } return nil }
// Set sets the components of the vector from a string of the form
// "float,float"
Set sets the components of the vector from a string of the form float float