test_call = fn () {
    ret = fn(){[1,fn(){[4,5,6]},3]}()[1]()[1]
    assert(ret == 5)
}

test_closure = fn () {
    make_func = fn (mut x) {
        mut n = 100
        fn () {
            n = n + 1
            x = x + 1 + n
        }
    }

    f = make_func(10)
    f()
    f()
    ret = f()

    assert(ret == 319)
}

test_sum = fn () {
    mut i = 1
    mut ret = 0
    while i <= 10 {
        ret = ret + i
        i = i + 1
    }

    assert(ret == 55)
}

test_fib = fn () {
    fib = fn (x) {
        if x < 2 {
            x
        } else {
            self(x - 2) + self(x -1)
        }
    }

    ret = fib(15)

    assert(ret == 610)
}

test_call()
test_closure()
test_sum()
test_fib()