trafi/maybe-result-cpp

Maybe Result implementation for C++

Maybe Result

Maybe Result is a return value wrapper that can contain either a value T or error E. It borrows ideas heavily from the C++17's std::experimental::optional, Rust's std::result and the std::expected that was proposed but not yet accepted for C++17.

• Browse reference docs.
• See example usage.

How is it different from std::experimental::optional?

Has a value for error instead of nullopt.

How is it different from std::expected?

It does not require the error to be an exception, and does not fall back to exceptions. All values must be checked, similar to std::experimental::optional.

Setting up

This is header-only library. We recommend to add src to included directories, so that the include would be:

#include <maybe/result.hpp>

A C++ compiler shat supports C++14 is required. You can use -std=c++14 flag for sufficiently recent versions of GCC (4.9) or CLANG (3.7).

Warning! Library is highly experimental and is not guaranteed to work.

Running tests

Library requires std::experimental::optional implementation, location of which can be specified with -DEXPERIMENTAL_OPTIONAL_INCLUDE flag:

cmake -DEXPERIMENTAL_OPTIONAL_INCLUDE=../path/to/optional .
make tests && ./tests/tests

There is a script that does this automatically:

./dev/run-tests.sh

In addition to this, you can run tests on all supported compilers using docker:

./dev/docker-run-tests.sh

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.