cpp_generators

This is my implementation of generators using C++20 coroutines

For example uses, see coroutine_iterator.cpp

If you have suggestions, feature requests, or other comments, feel free to open an issue or a pull request.

generator<T, R>

The return object type of a generator.

• T is the type of the values the generator will yield.
• R represents the return type of the generator (the type co_return will be called with). Defaults to void.

A generator object is a forward-iterable range, so if f returns one, the following loop head is valid:

for (auto x : f())

To implement a generator, simply declare a function that returns one and use co_yield in its body, like this:

generator<int> f() {
    co_yield 1;
    co_yield 2;
    co_return;
}

Note that the co_return is necessary because otherwise there would be no return statement at the end of a non-void function.

yield_from<Range>

An awaitable that will insert the values of the given range into the awaiting coroutine. Note that the return object must support yielding multiple values at once (for example, by placing them in a queue), or else this will only yield the last value. To use, just insert a call to co_await yield_from(my_range); into your coroutine.

For example, the following generator will yield the numbers from 1 to 10.

generator<int> f() {
    std::array a{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    co_await yield_from(a);
}

If Range is a generator with a non-void return type, co_await yield_from(gen) returns the generator's return value.