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Updated monadic interface for PR2505r1 #137

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6d7bb81
added transform_or monadic function to conform to PR2505r1
georg-emg Feb 23, 2023
e089feb
Wrapped all non-standard monadic function in a macro TL_EXPECTED_STRICT
georg-emg Feb 23, 2023
3ed12a5
readded support for transform() with function returning void when TL_…
georg-emg Feb 23, 2023
9d9bdd7
removed superfluous std::enable_if's when TL_EXPECTED_STRICT is defined
georg-emg Feb 23, 2023
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102 changes: 89 additions & 13 deletions include/tl/expected.hpp
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -1333,6 +1333,7 @@ class expected : private detail::expected_move_assign_base<T, E>,
#endif
#endif

#ifndef TL_EXPECTED_STRICT
#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
!defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
template <class F> TL_EXPECTED_11_CONSTEXPR auto map(F &&f) & {
Expand Down Expand Up @@ -1376,6 +1377,7 @@ class expected : private detail::expected_move_assign_base<T, E>,
}
#endif
#endif
#endif

#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
!defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
Expand Down Expand Up @@ -1421,6 +1423,7 @@ class expected : private detail::expected_move_assign_base<T, E>,
#endif
#endif

#ifndef TL_EXPECTED_STRICT
#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
!defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
template <class F> TL_EXPECTED_11_CONSTEXPR auto map_error(F &&f) & {
Expand Down Expand Up @@ -1506,6 +1509,7 @@ class expected : private detail::expected_move_assign_base<T, E>,
return map_error_impl(std::move(*this), std::forward<F>(f));
}
#endif
#endif
#endif
template <class F> expected TL_EXPECTED_11_CONSTEXPR or_else(F &&f) & {
return or_else_impl(*this, std::forward<F>(f));
Expand All @@ -1523,6 +1527,49 @@ class expected : private detail::expected_move_assign_base<T, E>,
template <class F> expected constexpr or_else(F &&f) const && {
return or_else_impl(std::move(*this), std::forward<F>(f));
}
#endif
#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
!defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
template <class F> TL_EXPECTED_11_CONSTEXPR auto transform_or(F &&f) & {
return map_error_impl(*this, std::forward<F>(f));
}
template <class F> TL_EXPECTED_11_CONSTEXPR auto transform_or(F &&f) && {
return map_error_impl(std::move(*this), std::forward<F>(f));
}
template <class F> constexpr auto transform_or(F &&f) const & {
return map_error_impl(*this, std::forward<F>(f));
}
template <class F> constexpr auto transform_or(F &&f) const && {
return map_error_impl(std::move(*this), std::forward<F>(f));
}
#else
template <class F>
TL_EXPECTED_11_CONSTEXPR decltype(map_error_impl(std::declval<expected &>(),
std::declval<F &&>()))
transform_or(F &&f) & {
return map_error_impl(*this, std::forward<F>(f));
}
template <class F>
TL_EXPECTED_11_CONSTEXPR decltype(map_error_impl(std::declval<expected &&>(),
std::declval<F &&>()))
transform_or(F &&f) && {
return map_error_impl(std::move(*this), std::forward<F>(f));
}
template <class F>
constexpr decltype(map_error_impl(std::declval<const expected &>(),
std::declval<F &&>()))
transform_or(F &&f) const & {
return map_error_impl(*this, std::forward<F>(f));
}

#ifndef TL_EXPECTED_NO_CONSTRR
template <class F>
constexpr decltype(map_error_impl(std::declval<const expected &&>(),
std::declval<F &&>()))
transform_or(F &&f) const && {
return map_error_impl(std::move(*this), std::forward<F>(f));
}
#endif
#endif
constexpr expected() = default;
constexpr expected(const expected &rhs) = default;
Expand Down Expand Up @@ -2208,15 +2255,19 @@ auto expected_map_impl(Exp &&exp, F &&f) -> expected<void, err_t<Exp>> {
template <class Exp, class F,
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
class Ret = decltype(detail::invoke(std::declval<F>(),
std::declval<Exp>().error())),
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
std::declval<Exp>().error()))
#ifndef TL_EXPECTED_STRICT
, detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr
#endif
>
constexpr auto map_error_impl(Exp &&exp, F &&f) {
using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;
return exp.has_value()
? result(*std::forward<Exp>(exp))
: result(unexpect, detail::invoke(std::forward<F>(f),
std::forward<Exp>(exp).error()));
}
#ifndef TL_EXPECTED_STRICT
template <class Exp, class F,
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
class Ret = decltype(detail::invoke(std::declval<F>(),
Expand All @@ -2231,18 +2282,23 @@ auto map_error_impl(Exp &&exp, F &&f) {
detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
return result(unexpect, monostate{});
}
#endif
template <class Exp, class F,
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
class Ret = decltype(detail::invoke(std::declval<F>(),
std::declval<Exp>().error())),
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
std::declval<Exp>().error()))
#ifndef TL_EXPECTED_STRICT
, detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr
#endif
>
constexpr auto map_error_impl(Exp &&exp, F &&f) {
using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;
return exp.has_value()
? result()
: result(unexpect, detail::invoke(std::forward<F>(f),
std::forward<Exp>(exp).error()));
}
#ifndef TL_EXPECTED_STRICT
template <class Exp, class F,
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
class Ret = decltype(detail::invoke(std::declval<F>(),
Expand All @@ -2257,12 +2313,16 @@ auto map_error_impl(Exp &&exp, F &&f) {
detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
return result(unexpect, monostate{});
}
#endif
#else
template <class Exp, class F,
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
class Ret = decltype(detail::invoke(std::declval<F>(),
std::declval<Exp>().error())),
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
std::declval<Exp>().error()))
#ifndef TL_EXPECTED_STRICT
, detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr
#endif
>
constexpr auto map_error_impl(Exp &&exp, F &&f)
-> expected<exp_t<Exp>, detail::decay_t<Ret>> {
using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;
Expand All @@ -2273,6 +2333,7 @@ constexpr auto map_error_impl(Exp &&exp, F &&f)
std::forward<Exp>(exp).error()));
}

#ifndef TL_EXPECTED_STRICT
template <class Exp, class F,
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
class Ret = decltype(detail::invoke(std::declval<F>(),
Expand All @@ -2287,12 +2348,16 @@ auto map_error_impl(Exp &&exp, F &&f) -> expected<exp_t<Exp>, monostate> {
detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
return result(unexpect, monostate{});
}
#endif

template <class Exp, class F,
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
class Ret = decltype(detail::invoke(std::declval<F>(),
std::declval<Exp>().error())),
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
std::declval<Exp>().error()))
#ifndef TL_EXPECTED_STRICT
, detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr
#endif
>
constexpr auto map_error_impl(Exp &&exp, F &&f)
-> expected<exp_t<Exp>, detail::decay_t<Ret>> {
using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;
Expand All @@ -2303,6 +2368,7 @@ constexpr auto map_error_impl(Exp &&exp, F &&f)
std::forward<Exp>(exp).error()));
}

#ifndef TL_EXPECTED_STRICT
template <class Exp, class F,
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
class Ret = decltype(detail::invoke(std::declval<F>(),
Expand All @@ -2318,19 +2384,23 @@ auto map_error_impl(Exp &&exp, F &&f) -> expected<exp_t<Exp>, monostate> {
return result(unexpect, monostate{});
}
#endif
#endif

#ifdef TL_EXPECTED_CXX14
template <class Exp, class F,
class Ret = decltype(detail::invoke(std::declval<F>(),
std::declval<Exp>().error())),
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
std::declval<Exp>().error()))
#ifndef TL_EXPECTED_STRICT
, detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr
#endif
>
constexpr auto or_else_impl(Exp &&exp, F &&f) {
static_assert(detail::is_expected<Ret>::value, "F must return an expected");
return exp.has_value() ? std::forward<Exp>(exp)
: detail::invoke(std::forward<F>(f),
std::forward<Exp>(exp).error());
}

#ifndef TL_EXPECTED_STRICT
template <class Exp, class F,
class Ret = decltype(detail::invoke(std::declval<F>(),
std::declval<Exp>().error())),
Expand All @@ -2341,18 +2411,23 @@ detail::decay_t<Exp> or_else_impl(Exp &&exp, F &&f) {
std::forward<Exp>(exp).error()),
std::forward<Exp>(exp));
}
#endif
#else
template <class Exp, class F,
class Ret = decltype(detail::invoke(std::declval<F>(),
std::declval<Exp>().error())),
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
std::declval<Exp>().error()))
#ifndef TL_EXPECTED_STRICT
, detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr
#endif
>
auto or_else_impl(Exp &&exp, F &&f) -> Ret {
static_assert(detail::is_expected<Ret>::value, "F must return an expected");
return exp.has_value() ? std::forward<Exp>(exp)
: detail::invoke(std::forward<F>(f),
std::forward<Exp>(exp).error());
}

#ifndef TL_EXPECTED_STRICT
template <class Exp, class F,
class Ret = decltype(detail::invoke(std::declval<F>(),
std::declval<Exp>().error())),
Expand All @@ -2364,6 +2439,7 @@ detail::decay_t<Exp> or_else_impl(Exp &&exp, F &&f) {
std::forward<Exp>(exp));
}
#endif
#endif
} // namespace detail

template <class T, class E, class U, class F>
Expand Down
110 changes: 110 additions & 0 deletions tests/extensions.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -803,6 +803,116 @@ TEST_CASE("Transform error extensions", "[extensions.transform_error]") {

}

TEST_CASE("transform_or", "[extensions.transform_or]") {
auto mul2 = [](int a) { return a * 2; };
auto ret_void = [](int a) { (void)a; };

{
tl::expected<int, int> e = 21;
auto ret = e.transform_or(mul2);
REQUIRE(ret);
REQUIRE(*ret == 21);
}

{
const tl::expected<int, int> e = 21;
auto ret = e.transform_or(mul2);
REQUIRE(ret);
REQUIRE(*ret == 21);
}

{
tl::expected<int, int> e = 21;
auto ret = std::move(e).transform_or(mul2);
REQUIRE(ret);
REQUIRE(*ret == 21);
}

{
const tl::expected<int, int> e = 21;
auto ret = std::move(e).transform_or(mul2);
REQUIRE(ret);
REQUIRE(*ret == 21);
}

{
tl::expected<int, int> e(tl::unexpect, 21);
auto ret = e.transform_or(mul2);
REQUIRE(!ret);
REQUIRE(ret.error() == 42);
}

{
const tl::expected<int, int> e(tl::unexpect, 21);
auto ret = e.transform_or(mul2);
REQUIRE(!ret);
REQUIRE(ret.error() == 42);
}

{
tl::expected<int, int> e(tl::unexpect, 21);
auto ret = std::move(e).transform_or(mul2);
REQUIRE(!ret);
REQUIRE(ret.error() == 42);
}

{
const tl::expected<int, int> e(tl::unexpect, 21);
auto ret = std::move(e).transform_or(mul2);
REQUIRE(!ret);
REQUIRE(ret.error() == 42);
}

{
tl::expected<int, int> e = 21;
auto ret = e.transform_or(ret_void);
REQUIRE(ret);
}

{
const tl::expected<int, int> e = 21;
auto ret = e.transform_or(ret_void);
REQUIRE(ret);
}

{
tl::expected<int, int> e = 21;
auto ret = std::move(e).transform_or(ret_void);
REQUIRE(ret);
}

{
const tl::expected<int, int> e = 21;
auto ret = std::move(e).transform_or(ret_void);
REQUIRE(ret);
}

{
tl::expected<int, int> e(tl::unexpect, 21);
auto ret = e.transform_or(ret_void);
REQUIRE(!ret);
}

{
const tl::expected<int, int> e(tl::unexpect, 21);
auto ret = e.transform_or(ret_void);
REQUIRE(!ret);
}

{
tl::expected<int, int> e(tl::unexpect, 21);
auto ret = std::move(e).transform_or(ret_void);
REQUIRE(!ret);
}

{
const tl::expected<int, int> e(tl::unexpect, 21);
auto ret = std::move(e).transform_or(ret_void);
REQUIRE(!ret);
}

}

struct S {
int x;
};
Expand Down