Error Handling in Rust that Every Beginner should Know (Go way)

circle_equation.go

func square(s string) (float64, error) {
	i, e := strconv.ParseFloat(s, 64)
	return i * i, e
}
func calculate(x string, y string) (*float64, error) {
	x2, e := square(x)
	if e != nil {
		return nil, e
	}
	y2, e := square(y)
	if e != nil {
		return nil, e
	}
	r := math.Sqrt(x2 + y2)
	return &r, nil
}
r, _ := calculate("2", "2")
println(*r) // +2.828427e+000
_, e := calculate("2", "?")
println(e.Error()) // strconv.ParseFloat: parsing "?": invalid syntax