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Add option::transform and option::or_else

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This commit is contained in:
Steven Le Rouzic
2024-11-02 20:18:32 +01:00
parent 7e8e2ef0be
commit c6a4aa13c2
2 changed files with 82 additions and 0 deletions
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47
asl/option.hpp
View File

@ -429,6 +429,53 @@ public:
}
return un_cvref_t<result_of_t<F(T)>>{};
}
template<typename F>
constexpr auto transform(F&& f) &
{
using U = un_cvref_t<result_of_t<F(T&)>>;
if (has_value())
{
return option<U>{ invoke(ASL_FWD(f), value()) };
}
return option<U>{};
}
template<typename F>
constexpr auto transform(F&& f) const&
{
using U = un_cvref_t<result_of_t<F(const T&)>>;
if (has_value())
{
return option<U>{ invoke(ASL_FWD(f), value()) };
}
return option<U>{};
}
template<typename F>
constexpr auto transform(F&& f) &&
{
using U = un_cvref_t<result_of_t<F(T)>>;
if (has_value())
{
return option<U>{ invoke(ASL_FWD(f), ASL_MOVE(value())) };
}
return option<U>{};
}
template<typename F>
constexpr option or_else(F&& f) const&
requires is_same<un_cvref_t<result_of_t<F()>>, option>
{
return has_value() ? *this : invoke(ASL_FWD(f));
}
template<typename F>
constexpr option or_else(F&& f) &&
requires is_same<un_cvref_t<result_of_t<F()>>, option>
{
return has_value() ? ASL_MOVE(*this) : invoke(ASL_FWD(f));
}
};
template<typename T>

35
asl/tests/option_tests.cpp
View File

@ -241,3 +241,38 @@ ASL_TEST(and_then)
static_assert(asl::is_same<decltype(b2), asl::option<float>>);
ASL_TEST_ASSERT(!b2.has_value());
}
ASL_TEST(transform)
{
asl::option<int> a = 5;
asl::option<int> b;
auto fn = [](int x) -> float { return static_cast<float>(x) + 0.5F; };
auto a2 = a.transform(fn);
static_assert(asl::is_same<decltype(a2), asl::option<float>>);
ASL_TEST_ASSERT(a2.has_value());
ASL_TEST_EXPECT(a2.value() == 5.5F);
auto b2 = b.transform(fn);
static_assert(asl::is_same<decltype(b2), asl::option<float>>);
ASL_TEST_ASSERT(!b2.has_value());
}
ASL_TEST(or_else)
{
asl::option<int> a = 5;
asl::option<int> b;
auto fn = []() -> asl::option<int> { return 12; };
auto a2 = a.or_else(fn);
static_assert(asl::is_same<decltype(a2), asl::option<int>>);
ASL_TEST_ASSERT(a2.has_value());
ASL_TEST_EXPECT(a2.value() == 5);
auto b2 = b.or_else(fn);
static_assert(asl::is_same<decltype(b2), asl::option<int>>);
ASL_TEST_ASSERT(b2.has_value());
ASL_TEST_EXPECT(b2.value() == 12);
}