simple_tasks.cpp

// The MIT License (MIT)
//
// Copyright (c) 2021 Mateusz Pusz
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
 
#include <mp-coro/sync_await.h>
#include <mp-coro/task.h>
#include <iostream>
 
mp_coro::task<int> foo() {
    std::cout << "foo(): about to return\n";
    co_return 42;
}
 
mp_coro::task<int> bar() {
    auto result = foo();
    std::cout << "bar(): about to co_await\n";
    const int i = co_await result;
    std::cout << "i = " << i << '\n';
    std::cout << "bar(): about to return\n";
    co_return i + 23;
}
 
int val = 123;
 
mp_coro::task<int &> ref() { co_return val; }
 
mp_coro::task<> baz() {
    std::cout << co_await foo() << '\n';
    std::cout << co_await ref() << '\n';
}
 
mp_coro::task<> empty() {
    std::cout << "empty\n";
    co_return;
}
 
mp_coro::task<> multiple_await() {
    auto task = foo();
    std::cout << "Result #1: " << co_await task << '\n';
    std::cout << "Result #2: " << co_await task << '\n';
    std::cout << "Result #3: " << co_await std::move(task) << '\n';
}
 
int main() {
    try {
        auto task = bar();
        std::cout << "i = " << sync_await(task) << '\n';
        sync_await(baz());
        sync_await(empty());
        std::cout << sync_await(ref()) << '\n';
        sync_await(multiple_await());
    } catch (const std::exception &ex) {
        std::cout << "Unhandled exception: " << ex.what() << '\n';
    }
}