srctree

private:

struct CoroutineSentinel {

friend constexpr bool operator!=(auto const &generator_iterator, CoroutineSentinel const &) {

return !generator_iterator.handle.done();

}

};

 

struct GeneratorIterator {

Handle handle;

 

GeneratorIterator &operator++() {

handle.resume();

return *this;

}

 

T &operator*() const { return handle.promise().maybe_value.value(); }

T *operator->() const { return &**this; }

};

 

public:

GeneratorIterator begin() { return {handle_}; }

CoroutineSentinel end() { return {}; }

 

etest::test("range-based for loop", [] {

auto gen = []() -> util::Generator<char> {

co_yield 'a';

co_yield 'b';

co_yield 'c';

}();

 

char current_expectation = 'a';

for (auto c : gen) {

expect_eq(current_expectation, c);

++current_expectation;

}

 

expect_eq('d', current_expectation);

});

 

etest::test("boring for loop", [] {

auto gen = []() -> util::Generator<std::pair<char, int>> {

co_yield {'a', 2};

}();

 

int iterations{};

for (auto it = std::begin(gen); it != std::end(gen); ++it) {

expect_eq(it->first, 'a');

expect_eq(it->second, 2);

++iterations;

}

 

expect_eq(1, iterations);

});