type assertion of custom type in go using interface{}

Question

Hi Im new to go and I'm trying implement data structures and algos in go as a learning process. I am trying to interfaces as generics values but I cannot seem to get my custom type of vertex to function properly. I have attached a link to a go playground

type Vertex struct{
    Adjacent DoubleLinkedList.DLinkedList
    Weight  int 
    Origin  int
}

type UGraph struct{
    Vertices map[int]DoubleLinkedList.DLinkedList
    Weight  int 
    counter int 
    VerticesList []*Vertex
}

func (UG *UGraph) BFS(node *Vertex, Value interface{})(int) {

    visited := make(map[*Vertex]bool) // map that acts as a set

    var queue Queue.Queue
    queue.Enqueue(node)

    for queue.Store.Size > 0 {
        V, _ := queue.Dequeue()
        nodes := UG.Vertices[((V).(Vertex).Origin).(int64)]
        
        head := nodes.Head
        for head.Next != nil {

            head = head.Next

            if head.Value == Value{
                return head.Value.Origin
            }

            if visited[(head.Value.Origin).(int64)] != true{
                visited[head.Value.Origin] = true
                queue.Enqueue(head)
            }
        }
    }
    return 0 
}

https://go.dev/play/p/s3t9LCfBlRI

Answer 1

If I understand correctly your issue, this seems to be your starting point:

You need a Queue with generics support. Then you need to update all structures to handle a T generic type like in the example below.

Be aware that once you have a type T in your struct, your method signature must be updated

You don’t need to use Generics on each type. You may want to use a field with an existing type like Queue[int]

Here we will consider you want all be generic

Enjoy

type DListNode[T any] struct {
    Prev  *DListNode[T]
    Next  *DListNode[T]
    Value T
}

func (DLL *DLinkedList[T]) AddFront(value T) { 
…
}

type Queue[T any] struct {
    Store    DLinkedList[T] // consider store a pointer 
    Capacity int
    Front    T
    Rear     T
}

func (QQ *Queue[T]) Enqueue(value T) error {
…
}

func (QQ *Queue[T]) Dequeue() (T, error) {
if QQ.isEmpty() {
        var zero T
        return zero, fmt.Errorf("Queue is currently Empty")
    }
    …

}

…

// omitting some steps, you can see that you need this in the end:
func (UG *UGraph[T]) BFS(node *Vertex[T], value T) T {