Function slice

subprojects/llama.cpp/common/jinja/value.cpp:71–115

 */
template<typename T>
static T slice(const T & array, int64_t start, int64_t stop, int64_t step = 1) {
    int64_t len = static_cast<int64_t>(array.size());
    int64_t direction = (step > 0) ? 1 : ((step < 0) ? -1 : 0);
    int64_t start_val = 0;
    int64_t stop_val = 0;
    if (direction >= 0) {
        start_val = start;
        if (start_val < 0) {
            start_val = std::max(len + start_val, (int64_t)0);
        } else {
            start_val = std::min(start_val, len);
        }

        stop_val = stop;
        if (stop_val < 0) {
            stop_val = std::max(len + stop_val, (int64_t)0);
        } else {
            stop_val = std::min(stop_val, len);
        }
    } else {
        start_val = len - 1;
        if (start_val < 0) {
            start_val = std::max(len + start_val, (int64_t)-1);
        } else {
            start_val = std::min(start_val, len - 1);
        }

        stop_val = -1;
        if (stop_val < -1) {
            stop_val = std::max(len + stop_val, (int64_t)-1);
        } else {
            stop_val = std::min(stop_val, len - 1);
        }
    }
    T result;
    if (direction == 0) {
        return result;
    }
    for (int64_t i = start_val; direction * i < direction * stop_val; i += step) {
        if (i >= 0 && i < len) {
            result.push_back(array[static_cast<size_t>(i)]);
        }
    }
    return result;
}

template<typename T>
static value empty_value_fn(const func_args &) {