#include <iostream>
#include <vector>

constexpr auto less_than = [](int value) {
    return [=](auto x) { return x < value;};
};

constexpr auto in = [](auto min, auto max) {
    return [=](auto x) {
        return min <= x && x <= max;
    };
};

constexpr auto empty = [](auto&& x){
    return std::empty(x);
};

main: () -> int = {
    i := 15;

    std::cout << inspect i -> std::string {
        is (less_than(10)) = "i less than 10";
        is (in(11,20)) = "i is between 11 and 20";
        is _ = "i is out of our interest";
    } << std::endl;

    if i is (less_than(20)) {
        std::cout << "less than 20" << std::endl;
    }

    if i is (in(10,30)) {
        std::cout << "i is between 10 and 30" << std::endl;
    }

    v : std::vector<int> = ();

    if empty(v) {
        std::cout << "v is empty" << std::endl;
    }

    if v is (empty) {
        std::cout << "v is empty" << std::endl;
    }
}