pub struct List[T] {
pub mut:
    head &ListNode[T] = unsafe { nil }
}

pub struct ListNode[T] {
pub mut:
    value T
    next  &ListNode[T] = unsafe { nil }
}

pub fn list_new[T]() List[T] {
    return List[T]{}
}

pub fn (mut l List[T]) add(value T) {
    mut node := &ListNode[T]{value, unsafe { nil }}
    if unsafe { l.head == nil } {
        l.head = node
    } else {
        node.next = l.head
        l.head = node
    }
}

fn test_generic_assign_reference_generic_struct() {
    mut list1 := list_new[string]()
    list1.add('hello')
    println(list1.head.value)
    assert list1.head.value == 'hello'

    mut list2 := list_new[int]()
    list2.add(100)
    println(list2.head.value)
    assert list2.head.value == 100

    mut list3 := list_new[f64]()
    list3.add(22.2)
    println(list3.head.value)
    assert list3.head.value == 22.2

    mut list4 := list_new[bool]()
    list4.add(true)
    println(list4.head.value)
    assert list4.head.value == true
}