menegaskan fungsi

Question

Di c ada makro assertdan saat berfungsi, saya tidak memiliki gambar seperti itu terutama karena tidak ada cara yang baik untuk mencetak string. Alhasil, saya mencoba membuat versi yang lebih baik dari assertuntuk c ++. Namun, saya terlalu memaksakannya sehingga saya memiliki sesuatu yang memperlambat waktu kompilasi, dan sesuatu yang tidak akan saya gunakan. Bagaimana cara memperbaikinya?

assert.hh

#ifndef ASSERT_HH
#define ASSERT_HH
#include <iostream>
#include <utility>
#include <tuple>

namespace turtle
{
    /* these macros are needed because #__VA_ARGS__ will include the comma in the string
     * for example: macro(...) __VA_ARGS__
     * macro(a,b) -> expands to "a,b"
     * instead of "a","b"
     */
#define TURTLE_FIRST_(a, ...) a
#define TURTLE_SECOND_(a, b, ...) b

#define TURTLE_FIRST(...) TURTLE_FIRST_(__VA_ARGS__,)
#define TURTLE_SECOND(...) TURTLE_SECOND_(__VA_ARGS__,)

#define TURTLE_EMPTY()

#define TURTLE_EVAL(...) TURTLE_EVAL1024(__VA_ARGS__)
#define TURTLE_EVAL1024(...) TURTLE_EVAL512(TURTLE_EVAL512(__VA_ARGS__))
#define TURTLE_EVAL512(...) TURTLE_EVAL256(TURTLE_EVAL256(__VA_ARGS__))
#define TURTLE_EVAL256(...) TURTLE_EVAL128(TURTLE_EVAL128(__VA_ARGS__))
#define TURTLE_EVAL128(...) TURTLE_EVAL64(TURTLE_EVAL64(__VA_ARGS__))
#define TURTLE_EVAL64(...) TURTLE_EVAL32(TURTLE_EVAL32(__VA_ARGS__))
#define TURTLE_EVAL32(...) TURTLE_EVAL16(TURTLE_EVAL16(__VA_ARGS__))
#define TURTLE_EVAL16(...) TURTLE_EVAL8(TURTLE_EVAL8(__VA_ARGS__))
#define TURTLE_EVAL8(...) TURTLE_EVAL4(TURTLE_EVAL4(__VA_ARGS__))
#define TURTLE_EVAL4(...) TURTLE_EVAL2(TURTLE_EVAL2(__VA_ARGS__))
#define TURTLE_EVAL2(...) TURTLE_EVAL1(TURTLE_EVAL1(__VA_ARGS__))
#define TURTLE_EVAL1(...) __VA_ARGS__

#define TURTLE_DEFER1(m) m TURTLE_EMPTY()
#define TURTLE_DEFER2(m) m TURTLE_EMPTY TURTLE_EMPTY()()

#define TURTLE_IS_PROBE(...) TURTLE_SECOND(__VA_ARGS__, 0)
#define TURTLE_PROBE() ~, 1

#define TURTLE_CAT(a, b) a ## b

#define TURTLE_NOT(x) TURTLE_IS_PROBE(TURTLE_CAT(TURTLE__NOT_, x))
#define TURTLE__NOT_0 TURTLE_PROBE()

#define TURTLE_BOOL(x) TURTLE_NOT(TURTLE_NOT(x))

#define TURTLE_IF_ELSE(condition) TURTLE__IF_ELSE(TURTLE_BOOL(condition))
#define TURTLE__IF_ELSE(condition) TURTLE_CAT(TURTLE__IF_, condition)

#define TURTLE__IF_1(...) __VA_ARGS__ TURTLE__IF_1_ELSE
#define TURTLE__IF_0(...)             TURTLE__IF_0_ELSE

#define TURTLE__IF_1_ELSE(...)
#define TURTLE__IF_0_ELSE(...) __VA_ARGS__

#define TURTLE_COMMA ,

#define TURTLE_HAS_ARGS(...) TURTLE_BOOL(TURTLE_FIRST(TURTLE__END_OF_ARGUMENTS_ __VA_ARGS__)())
#define TURTLE__END_OF_ARGUMENTS_() 0

#define TURTLE_MAP(m, first, ...)                               \
  m(first)                                                      \
  TURTLE_IF_ELSE(TURTLE_HAS_ARGS(__VA_ARGS__))(                 \
    TURTLE_COMMA TURTLE_DEFER2(TURTLE__MAP)()(m, __VA_ARGS__)   \
  )(                                                            \
    /* Do nothing, just terminate */                            \
  )
#define TURTLE__MAP() TURTLE_MAP
#define TURTLE__STRINGIZE(x) TURTLE___STRINGIZE(x)
#define TURTLE___STRINGIZE(x) #x
#define TURTLE_STRINGIZE(x) __FILE__ " line " TURTLE__STRINGIZE(__LINE__) ": assertion {" #x

    template<typename... Args, typename Text>
    constexpr auto assert_basic(const std::tuple<Args...> &arg, const Text &text)
    {
        if constexpr (sizeof...(Args) == 1) {
            if (!std::get<0>(arg)) {
                std::cerr << text << "} failed\n";
                return true;
            }
        } else {
            if (!std::get<0>(arg)) {
                std::cerr << text << "} failed -> "
                          << std::get<1>(arg) << '\n';
                return true;
            }
        }
        return false;
    }

    template<std::size_t Index, typename Result, typename... Args>
    constexpr auto assert_tuple_args_helper(const Result &result, const std::tuple<Args...> &tuple_args_basic)
    {
        if constexpr (Index >= sizeof...(Args)) {
            return result;
        } else if constexpr (Index + 1 >= sizeof...(Args) &&
                             std::is_convertible_v<std::tuple_element_t<Index, std::decay_t<decltype(tuple_args_basic)>>, int>) {
            return assert_tuple_args_helper<Index + 1>(std::tuple_cat(result,
                                                                      std::tuple<decltype(std::tuple{
                                                                              std::get<Index>(tuple_args_basic)})>{
                                                                              std::tuple{std::get<Index>(
                                                                                      tuple_args_basic)}}),
                                                       tuple_args_basic);
        } else if constexpr (
                std::is_convertible_v<std::tuple_element_t<Index, std::decay_t<decltype(tuple_args_basic)>>, int>
                &&
                std::is_convertible_v<std::tuple_element_t<Index + 1, std::decay_t<decltype(tuple_args_basic)>>, int>) {
            return assert_tuple_args_helper<Index + 1>(
                    std::tuple_cat(result, std::tuple<decltype(std::tuple{std::get<Index>(tuple_args_basic)})>{
                            std::tuple{std::get<Index>(tuple_args_basic)}}), tuple_args_basic);
        } else if constexpr (
                std::is_convertible_v<std::tuple_element_t<Index, std::decay_t<decltype(tuple_args_basic)>>, int>
                && !std::is_convertible_v<std::tuple_element_t<
                        Index + 1, std::decay_t<decltype(tuple_args_basic)>>, int>) {
            return assert_tuple_args_helper<Index + 2>(
                    std::tuple_cat(result, std::tuple<decltype(std::tuple{std::get<Index>(tuple_args_basic),
                                                                          std::get<Index + 1>(
                                                                                  tuple_args_basic)})>
                            {std::tuple{std::get<Index>(tuple_args_basic),
                                        std::get<Index + 1>(
                                                tuple_args_basic)}}), tuple_args_basic);
        }
    }

    template<std::size_t TupleIndex, typename Result, typename... Args>
    constexpr auto assert_tuple_text_indices_helper(const Result& result, std::size_t old_index, const std::tuple<Args...>& tuple)
    {
        if constexpr (TupleIndex < std::tuple_size_v<std::decay_t<decltype(tuple)>>) {
            std::size_t next_index = old_index + std::tuple_size_v<std::decay_t<decltype(std::get<TupleIndex>(tuple))>>;
            return assert_tuple_text_indices_helper<TupleIndex+1>(std::tuple_cat(result, std::tuple{old_index}), next_index, tuple);
        } else {
            return result;
        }
    }

    template<typename Text, typename... Args>
    constexpr auto assert(const Text& text, Args &&... args)
    {
        const auto &tuple_args = assert_tuple_args_helper<0>(std::tuple{}, std::tuple{args...});
        constexpr auto tuple_text_indices = assert_tuple_text_indices_helper<0>(std::tuple{}, 0, decltype(tuple_args){});
        [&]<std::size_t... Indices>(std::index_sequence<Indices...>) {
            if ((assert_basic(std::get<Indices>(tuple_args), text[std::get<Indices>(tuple_text_indices)]) | ...)) {
                std::exit(1);
            }
        }(std::make_index_sequence<std::tuple_size_v<std::decay_t<decltype(tuple_args)>>>{});
    }
}

#define assert(...) turtle::assert(std::array{TURTLE_EVAL(TURTLE_MAP(TURTLE_STRINGIZE, __VA_ARGS__))}, __VA_ARGS__)

#endif /* ASSERT_HH */

main.cc

#include "assert.hh"


/* testing */
int main()
{
    int a, b, c, d;
    std::cin >> a >> b >> c >> d;
    assert(__LINE__ % 2 == 1, a < b, "a must be less than b", b < c, "b must be less than c", c < d, "c must be less than d");
    assert(__LINE__ % 2 == 1, __FILE__[2] < 80);
}

Answer 1

Saat Anda mencari kemacetan kinerja, mungkin membantu untuk fokus pada bagian yang disebutkan TURTLE. ;) Tapi saya bahkan tidak berpikir itu masalah utama Anda di sini.

Sepertinya yang ingin Anda lakukan hanyalah melampirkan pesan ke pernyataan tersebut, bukan?

#define myAssert(x, msg) assert((x) && msg)

Ini berfungsi selama Anda berhati-hati untuk selalu menggandakan tanda kurung pada pemanggilan yang membutuhkan tanda kurung ganda:

myAssert(x < 2, "x is too large");
myAssert((foo<int,int> < 2), "foo<int,int> is too large");

Jika Anda ingin menghilangkan tanda kurung, saya akan mengurangi masalah itu menjadi "Bagaimana cara mengekstrak argumen makro terakhir dari paket?" Salah satu penjawab masuk akal menunjukkan bahwa Anda unask bahwa pertanyaan dan hanya menempatkan pesan sebagai argumen pertama:

#define myAssert(msg, ...) assert((__VA_ARGS__) && msg)
myAssert("x is too large", x < 2);
myAssert("foo<int,int> is too large", foo<int,int> < 2);