Fundamentals of garbage collection (2023)(learn.microsoft.com)

    -- circular linked list with one item
    repeat x = let xs = x:xs in xs

    function repeat(x) {
        function xs() {
            return [x, xs]; // [first, rest]
        }
        return xs;
    }

    class Thunk {
        constructor(f) { this.f = f; }
        get() { if (this.f) { this.v = (this.f)(); delete this.f; } return this.v; }
    }

    function repeat(x) {
        let xs = new Thunk(() => {
            return [x, xs]; // [first, rest]
        });
        return xs;
    }