struct Stack[T] {
mut:
    elements []T
}

pub fn (stack Stack[T]) is_empty() bool {
    return stack.elements.len == 0
}

pub fn (stack Stack[T]) peek() ?T {
    return if !stack.is_empty() { stack.elements.last() } else { none }
}

pub fn (stack Stack[T]) peek2() !T {
    return if !stack.is_empty() { stack.elements.last() } else { error('Stack is empty') }
}

@[heap]
struct Element {
mut:
    name  string
    value string
}

fn test_main() {
    mut parent := &Element{
        name: 'parent element'
    }
    mut stack := Stack[&Element]{}
}