CPPromise ========= .. image:: https://img.shields.io/travis/Determinant/cppromise.svg :target: https://github.com/Determinant/cppromise .. image:: https://img.shields.io/github/license/Determinant/cppromise.svg :target: https://github.com/Determinant/cppromise This is a lightweight C++14/17 compatiable implementation of promises (similar to Javascript Promise/A+). It allows type-safe polymorphic promises and incurs little runtime overhead. The runtime type-checking is enforced and supported by the underlying `any` type, an exception will be thrown when the resolved value types do not match the types expected in the subsequent computation. See `test.cpp` for detailed examples. API === .. code-block:: cpp typename promise_t(Func callback); Create a new promise object, the ``callback(promise_t pm)`` is invoked immediately after the object is constructed, so usually the user registers ``pm`` to some external logic which triggers ``pm.resolve()`` or ``pm.reject()`` when the time comes. .. code-block:: cpp template resolve(T result) const; Resolve the promise with value ``result``. This may trigger the other promises waiting for the current promise recursively. When a promise is triggered, the registered ``on_fulfilled()`` function will be invoked using ``result`` as the argument. .. code-block:: cpp tempalte reject(T reason) const; Reject the promise with value ``result``. This may reject the other promises waiting for the current promise recursively. When a promise is rejected, the registered ``on_rejected()`` function will be invoked using ``reason`` as the argument. .. code-block:: cpp template promise_t then(FuncFulfilled on_fulfilled) const; Create a new promise that waits for the resolution of the current promise. ``on_fulfilled`` will be called with result from the current promise when resolved. The rejection will skip the callback and pass on to the promises that follow the created promise. .. code-block:: cpp template promise_t fail(FuncRejected on_rejected) const; Create a new promise that waits for the rejection of the current promise. ``on_rejected`` will be called with reason from the current promise when rejected. The resolution will skip the callback and pass on to the promises that follow the created promise. .. code-block:: cpp template inline promise_t then(FuncFulfilled on_fulfilled, FuncRejected on_rejected) const; Create a promise that handles both resolution and rejection of the current promise.