mod example_iter {
    func main(args) {
        var counter = { index: 0 };
        var value = map::collect(
            @[counter]() {
                var index = counter{"index"};
                if math::less_than(index, 10) {
                    counter{"index"} = math::add(index, 1);
                    return { key: reflect::to_text(index), value: index };
                } else {
                    return null;
                }
            },
        );
        console::log_line(
            debug::debug(value, false),
        );
        console::log_line(
            debug::debug(
                map::collect(map::iter(value)),
                false,
            ),
        );
        var iter = iter::build([
            map::iter(value),
            [<func iter::filter>, @[](pair) {
                return math::equals(math::modulo(pair.value, 2), 0);
            }],
            [<func iter::map>, @[](pair) {
                return pair.key;
            }],
        ]);
        console::log_line(
            debug::debug(array::collect(iter), false),
        );

        var counter = { index: 0 };
        var value = array::collect(
            @[counter]() {
                var index = counter{"index"};
                if math::less_than(index, 10) {
                    counter{"index"} = math::add(index, 1);
                    return index;
                } else {
                    return null;
                }
            },
        );
        console::log_line(
            debug::debug(value, false),
        );
        console::log_line(
            debug::debug(
                array::collect(array::iter(value, true)),
                false,
            ),
        );

        var iter = iter::filter_map(
            array::iter(value, false),
            @[](value) {
                if math::equals(math::modulo(value, 2), 0) {
                    return reflect::to_text(value);
                } else {
                    return null;
                }
            },
        );
        console::log_line(
            debug::debug(array::collect(iter), false),
        );
        iter = iter::build([
            array::iter(value, true),
            [<func iter::filter>, @[](value) {
                return math::equals(math::modulo(value, 2), 0);
            }],
            [<func iter::map>, @[](value) {
                return reflect::to_text(value);
            }],
        ]);
        console::log_line(
            debug::debug(array::collect(iter), false),
        );
        value = [[0, 1], [2, 3]];
        iter = iter::build([
            array::iter(value, true),
            [<func iter::map>, @[](value) {
                return array::iter(value, false);
            }],
            [<func iter::flatten>],
        ]);
        console::log_line(
            debug::debug(array::collect(iter), false),
        );

        for item in iter::walk(-3, 7) {
            console::log_line(
                debug::debug(item, false),
            );
        }

        console::log_line(
            debug::debug(
                iter::fold(
                    iter::range(0, 10),
                    0,
                    @[](accum, value) { return math::add(accum, value); },
                ),
                false,
            ),
        );
        console::log_line(
            debug::debug(
                iter::find(
                    iter::walk(10, -10),
                    @[](value) { return math::equals(value, 5); },
                ),
                false,
            ),
        );
        console::log_line(
            debug::debug(
                iter::find_map(
                    iter::walk(10, -10),
                    @[](value) {
                        if math::equals(value, 5) {
                            return math::negate(value);
                        } else {
                            return null;
                        }
                    },
                ),
                false,
            ),
        );
        console::log_line(
            debug::debug(
                iter::position(
                    iter::walk(-3, 7),
                    @[](value) { return math::equals(value, 0); },
                ),
                false,
            ),
        );
        console::log_line(
            debug::debug(
                iter::any(
                    iter::walk(-3, 7),
                    @[](value) { return math::equals(value, 0); },
                ),
                false,
            ),
        );
        console::log_line(
            debug::debug(
                iter::all(
                    iter::walk(-3, 7),
                    @[](value) { return math::equals(value, 0); },
                ),
                false,
            ),
        );
        console::log_line(
            debug::debug(
                iter::compared_by(
                    iter::walk(-3, 7),
                    @[](a, b) { return math::greater_than(a, b); },
                ),
                false,
            ),
        );
        console::log_line(
            debug::debug(
                array::collect(
                    iter::chain([
                        iter::range(0, 5),
                        iter::range(10, 15),
                    ]),
                ),
                false,
            ),
        );
        console::log_line(
            debug::debug(
                array::collect(
                    iter::zip([
                        iter::range(0, 5),
                        iter::range(10, 15),
                    ]),
                ),
                false,
            ),
        );
        console::log_line(
            debug::debug(
                array::collect(
                    iter::chunks(
                        iter::range(0, 5),
                        2,
                    ),
                ),
                false,
            ),
        );
    }
}