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Constexpr fixes

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This commit is contained in:
Simon Brand
2017-10-24 15:46:07 +01:00
parent 0df06afe8d
commit 1b9d589024
2 changed files with 17 additions and 30 deletions
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29
optional.hpp
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@ -337,6 +337,9 @@ template <class T> class optional : private detail::optional_storage_base<T> {
using base = detail::optional_storage_base<T>;
public:
// The different versions for C++14 and 11 are needed because deduced return
// types are not SFINAE-safe. C.f.
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0826r0.html
#ifdef TL_OPTIONAL_CXX14
/// \group and_then
/// Carries out some operation which returns an optional on the stored object
@ -456,23 +459,21 @@ public:
/// `*this` is empty, otherwise an `optional<U>` is constructed from the
/// return value of `std::invoke(std::forward<F>(f), value())` and is
/// returned. \group map \synopsis template <class F> auto map(F &&f) &;
template <class F> auto map(F &&f) & {
template <class F> constexpr auto map(F &&f) & {
return map_impl(*this, std::forward<F>(f));
}
template <class F> auto map(F &&f) && {
template <class F> constexpr auto map(F &&f) && {
return map_impl(std::move(*this), std::forward<F>(f));
}
template <class F> auto map(F &&f) const & {
template <class F> constexpr auto map(F &&f) const & {
return map_impl(*this, std::forward<F>(f));
}
#ifndef TL_OPTIONAL_NO_CONSTRR
template <class F> auto map(F &&f) const && {
template <class F> constexpr auto map(F &&f) const && {
return map_impl(std::move(*this), std::forward<F>(f));
}
#endif
#else
/// \brief Carries out some operation on the stored object if there is one.
/// \returns Let `U` be the result of `std::invoke(std::forward<F>(f),
@ -481,26 +482,30 @@ public:
/// return value of `std::invoke(std::forward<F>(f), value())` and is
/// returned. \group map \synopsis template <class F> auto map(F &&f) &;
template <class F>
decltype(map_impl(std::declval<optional &>(), std::declval<F &&>()))
TL_OPTIONAL_11_CONSTEXPR decltype(map_impl(std::declval<optional &>(),
std::declval<F &&>()))
map(F &&f) & {
return map_impl(*this, std::forward<F>(f));
}
template <class F>
decltype(map_impl(std::declval<optional &&>(), std::declval<F &&>()))
TL_OPTIONAL_11_CONSTEXPR decltype(map_impl(std::declval<optional &&>(),
std::declval<F &&>()))
map(F &&f) && {
return map_impl(std::move(*this), std::forward<F>(f));
}
template <class F>
decltype(map_impl(std::declval<const optional &>(), std::declval<F &&>()))
constexpr decltype(map_impl(std::declval<const optional &>(),
std::declval<F &&>()))
map(F &&f) const & {
return map_impl(*this, std::forward<F>(f));
}
#ifndef TL_OPTIONAL_NO_CONSTRR
template <class F>
decltype(map_impl(std::declval<const optional &&>(), std::declval<F &&>()))
constexpr decltype(map_impl(std::declval<const optional &&>(),
std::declval<F &&>()))
map(F &&f) const && {
return map_impl(std::move(*this), std::forward<F>(f));
}
@ -1316,7 +1321,7 @@ template <class Opt, class F,
class Ret = decltype(detail::invoke(std::declval<F>(),
*std::declval<Opt>())),
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
auto map_impl(Opt &&opt, F &&f) {
constexpr auto map_impl(Opt &&opt, F &&f) {
return opt.has_value()
? detail::invoke(std::forward<F>(f), *std::forward<Opt>(opt))
: optional<Ret>(nullopt);
@ -1340,7 +1345,7 @@ template <class Opt, class F,
*std::declval<Opt>())),
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
auto map_impl(Opt &&opt, F &&f) -> optional<Ret> {
constexpr auto map_impl(Opt &&opt, F &&f) -> optional<Ret> {
return opt.has_value()
? detail::invoke(std::forward<F>(f), *std::forward<Opt>(opt))
: optional<Ret>(nullopt);

18
tests/extensions.cpp
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@ -128,34 +128,16 @@ TEST_CASE("Monadic operations", "[monadic]") {
constexpr auto o16r = o16.map(get_int);
STATIC_REQUIRE(*o16r == 42);
constexpr tl::optional<int> o18 = 42;
constexpr auto opt_int = tl::make_optional(get_int);
constexpr auto o18r = o18.map(opt_int);
STATIC_REQUIRE(*o18r == 42);
constexpr tl::optional<int> o20 = 42;
constexpr auto o20r = std::move(o20).map(get_int);
STATIC_REQUIRE(*o20r == 42);
constexpr tl::optional<int> o22 = 42;
constexpr auto o22r = std::move(o22).map(opt_int);
STATIC_REQUIRE(*o22r == 42);
constexpr tl::optional<int> o32 = tl::nullopt;
constexpr auto o32r = o32.map(get_int);
STATIC_REQUIRE(!o32r);
constexpr tl::optional<int> o34 = tl::nullopt;
constexpr auto o34r = o34.map(opt_int);
STATIC_REQUIRE(!o34r);
constexpr tl::optional<int> o36 = tl::nullopt;
constexpr auto o36r = std::move(o36).map(get_int);
STATIC_REQUIRE(!o36r);
constexpr tl::optional<int> o38 = tl::nullopt;
constexpr auto o38r = std::move(o38).map(opt_int);
STATIC_REQUIRE(!o38r);
#endif
}