Function test_lambdas

dlib/test/invoke.cpp:145–207

    // ----------------------------------------------------------------------------------------

    void test_lambdas()
    {
        {
            const auto f = [](int, float*, std::string&) -> long {return 1;};

            static_assert(std::is_same<dlib::callable_args<decltype(f)>,
                                       dlib::types_<int, float*, std::string&>
                                      >::value, "make this correct");
            
            static_assert(dlib::callable_nargs<decltype(f)>::value == 3, "bad");

            static_assert(std::is_same<dlib::callable_arg<0, decltype(f)>,
                                       int>::value, "make this correct");

            static_assert(std::is_same<dlib::callable_arg<1, decltype(f)>,
                                       float*>::value, "make this correct");

            static_assert(std::is_same<dlib::callable_arg<2, decltype(f)>,
                                       std::string&>::value, "make this correct");
            
            static_assert(std::is_same<dlib::callable_return<decltype(f)>,
                                       long>::value, "make this correct");
            
            static_assert(is_callable<decltype(f)>::value, "bad");
        }
                
        {
            std::string str = run1_str4;
            dlib::invoke([](int i, std::string ref1, const std::string& ref2, const std::string& ref3, std::string& ref4) {
                DLIB_TEST(i > 0);
                DLIB_TEST(ref1 == run1_str1);
                DLIB_TEST(ref2 == run1_str2);
                DLIB_TEST(ref3 == run1_str3);
                DLIB_TEST(ref4 == run1_str4);
                ref4 = run1_str5;
            }, 1, run1_str1, run1_str2, std::cref(run1_str3), std::ref(str));
            DLIB_TEST(str == run1_str5);
        }

        {
            std::string str = run1_str4;
            dlib::apply([](int i, std::string ref1, const std::string& ref2, const std::string& ref3, std::string& ref4) {
                DLIB_TEST(i > 0);
                DLIB_TEST(ref1 == run1_str1);
                DLIB_TEST(ref2 == run1_str2);
                DLIB_TEST(ref3 == run1_str3);
                DLIB_TEST(ref4 == run1_str4);
                ref4 = run1_str5;
            }, std::make_tuple(1, run1_str1, run1_str2, std::cref(run1_str3), std::ref(str)));
            DLIB_TEST(str == run1_str5);
        }

        {
            for (int i = -10 ; i <= 10 ; i++)
            {
                for (int j = -10 ; j <= 10 ; j++)
                {
                    DLIB_TEST(dlib::invoke([](int i, int j) {return i + j;}, i, j) == (i+j));