pub struct INode {
mut:
    heapindex u64
}

pub struct IHeap[T] {
mut:
    array []&T
    size  u64
}

pub fn create_iheap[T](capacity int) &IHeap[T] {
    mut h := &IHeap[T]{
        array: []&T{cap: capacity}
        size:  0
    }
    h.array << &T(unsafe { nil })
    return h
}

fn (mut h IHeap[T]) percolateup(hl u64, mut element T) {
    mut hole := hl
    for hole > 1 && element < h.array[int(hole / 2)] {
        // ^ Notice that '<' was not defined
        println("didnt define '<' for the INode")
        hole /= 2
    }
}

fn main() {
    heap := create_iheap[INode](3000000)
    println(heap)
}