Re: How to construct a tree data structure with differently static nodes types

[data pulverizer via Digitalmars-d-learn]

On Monday, 23 November 2020 at 01:20:04 UTC, data pulverizer 
wrote:
Hi all,

I am trying to construct a tree data structure composed of 
differently (statically) typed nodes. The basic case is a 
binary tree. So you have a node like:

```
struct Node(T)
{
  T value;
  Node* next;
  Node* prev;
}

void main()
{
  auto x = Node!(int)(2);
  auto y = Node!(double)(3.2);
  x.next = &y; //gives error
}
```
Error: cannot implicitly convert expression & y of type 
Node!double* to Node!int*

So implicity Node!(T) will produce an object with prev, and 
next type Node!(T)*. But once I give them different types:

```
struct Node(T, P, N)
{
  T value;
  Node!(P...)* prev;
  Node!(N...)* next;
}
```

I can no longer specify the types at all, they become 
circularly referenced. Would appreciate the solution to this.

Many thanks.

p.s. Something equivalent can be built using tuples but it's less 
convenient to write code for.