let list1 = [1, 2, 3, 4];
let list2 = ["foo", "bar", "foo", "bar"];

let mapper = macro(item) => { result = item + 1 };
let filtrator = macro(item) => {
    result = select item, NULL, {
        foo = item,
    },
};

assert |map mapper.result list1 == [2, 3, 4, 5]|;
assert |(map mapper.result [1, 2, 3, 4]) == [2, 3, 4, 5]|;
assert |map mapper.result [1, 2, 3, 4] == [2, 3, 4, 5]|;

assert |filter filtrator.result list2 == ["foo", "foo"]|;
assert |(filter filtrator.result ["foo", "bar", "foo", "bar"]) == ["foo", "foo"]|;
assert |filter filtrator.result ["foo", "bar", "foo", "bar"] == ["foo", "foo"]|;