playground.mojo

struct DemoStruct(CollectionElement, Stringable):
    var member1: List[Int]

    fn __init__(inout self, member1: List[Int]) -> None:
        self.member1 = member1
        print("Called constructor for " + str(self))

    fn __copyinit__(inout self, other: Self) -> None:
        self.member1 = other.member1
        print("Called copy constructor for " + str(self))

    fn __moveinit__(inout self, owned other: Self) -> None:
        self.member1 = other.member1
        print("Called move constructor for " + str(self))

    fn __del__(owned self) -> None:
        print("Calling destructor for " + str(self))

    fn __str__(self) -> String:
        var return_value = String("DemoStruct(List(")
        for index in range(len(self.member1) - 1):
            return_value += str(self.member1[index]) + ", "
        return_value += str(self.member1[-1]) + "))"
        return return_value


fn main() -> None:
    var demo_obj_1 = DemoStruct(List(1, 2, 3, 4, 5))
    var demo_obj_2 = demo_obj_1
    # Copy constructor is called here, even though no mutation occurs and Mojo is supposed to have copy-on-write/lazy copying semantics
    print(demo_obj_1)
    print(demo_obj_2)