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continuable v2.0.0 Release Notes

Release Date: 2018-01-30 // about 6 years ago

  • 👍 Zero cost futures now with error handling and co_await support

    In version 2.0 the library was heavily improved in multiple ways:

    Error handling

    👍 Usually it is inconvenient to handle error codes and exceptions in an asynchronous context, as we all know std::future supports error handling through exceptions already. We now introduce this capability to the continuable library while allowing error codes to be used as well.

    Consider the function cti::continuable<> get_bad_continuable() which always resolves through an error, then you may handle the error code or exception as following:

    get\_bad\_continuable() .then([] { // ... never invoked }) .then([] { // ... never invoked as well }) .fail([] (std::exception\_ptr e) { try { std::rethrow\_exception(e); } catch(std::exception const& e) { // Handle the exception here } });

    Abstracting callbacks as promises

    Since a callback may be called through an error or result the cri::promise class was added in order ro provide a similar interface to std::promise:

    auto http\_request(std::string url) {return cti::make\_continuable\<std::string\>([url = std::move(url)](cti::promise\<std::string\> /\*or auto&&\*/ promise) { // Perform the actual request through a different library,// resolve the promise upon completion of the task. promise.set\_value("\<html\> ... \</html\>"); // ...or promise.set\_exception(...);}); }

    👍 co_await support

    Experimental coroutine (co_await and co_return) support was added, this is available on MSVC 2017 and Clang 5.0.

    int i = co\_await cti::make\_continuable\<int\>([](auto&& promise) { promise.set\_value(0); });

    Minor improvements

    The library was improved in other ways:

    • constexpr and noexcept improvements
    • Compile-time improvements
    • 📚 Documentation improvements

    Header split

    Since the overall library size was increased the headers were split into smaller chunks.