Modular•9mo ago

Any ideas on implementing linked based structs in mojo?

I’m working on data structures in mojo and hit a roadblock at objects like linked lists and trees, how would I code a pointer to another object of the same type in mojo? and is there a way to use DTypePointers to ensure the result is string able?

1 Reply

benny•9mo ago

@value
struct Node[T: DType]:
    var value: SIMD[T, 1]
    var nxt: Pointer[Node[T]]

    fn __getitem__(self, i: Int) -> SIMD[T, 1]:
        return self.value

    fn __setitem__(inout self, i: Int, x: SIMD[T, 1]):
        self.value = x

    fn _set_next(inout self, owned nxt: Node[T]):
        self.nxt = Pointer[Node[T]].address_of(nxt)

    fn _get_next(self) -> Node[T]:
        ...

@value
struct Node[T: DType]:
    var value: SIMD[T, 1]
    var nxt: Pointer[Node[T]]

    fn __getitem__(self, i: Int) -> SIMD[T, 1]:
        return self.value

    fn __setitem__(inout self, i: Int, x: SIMD[T, 1]):
        self.value = x

    fn _set_next(inout self, owned nxt: Node[T]):
        self.nxt = Pointer[Node[T]].address_of(nxt)

    fn _get_next(self) -> Node[T]:
        ...

The above code works, just have no idea how to implement _get_next

@value
@register_passable
struct Node[T: DType]:
    var value: SIMD[T, 1]
    var next: Pointer[Node[T]]

@value
@register_passable
struct Node[T: DType]:
    var value: SIMD[T, 1]
    var next: Pointer[Node[T]]

The above code seems to be the correct answer, but throws errors when run, very complicated system errors, any ideas? I think the issue is with DType != Register passable, but how can you cast register passable types to printable values?

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Any ideas on implementing linked based structs in mojo?