Zen C++ Libraries

The Zen C++ libraries are a set of C++ headers and sources that aim to replace the C++ standard library. The libraries try to fill missing pieces in the existing C++ ecosystem, based on ideas taken from Haskell and Rust. In the future, it might even be possible to use the headers without any runtime dependency on the C++ standard library.

⚠️🧪 These libraries are experimental. They require a modern C++ compiler that supports at least C++20. The API may break regularly with the release of new versions. If you plan to make use of them right now, expect to refactor your code regularly.

What are the advantages?

You may consider Zen++ a standard library that isn't limited by the requirement of being backwards-compatible. Zen++ designed to be lightweight, fast and feature-complete, but without a stable ABI. This allows us to move faster than the STL is able to and fix inconsistencies much more easily.

What are the drawbacks?

• New updates might need a small refactor of your code. For example, a better Maybe<T> might require you to use strucutred binding declarations instead of using the dereferce operator. Only use this library if your team has enough bandwidth to keep in sync.
• No support for exceptions. The libraries use Either<L, R> to encode exceptions in the return type instead of throwing them. Moreover, if Zen++ is used as a replacement of the standard library, -fno-exceptions or something equivalent is required.
• No RTTI support. For performance reasons, all polymorphic information in this library is encoded using enums or something similar. Moreover, if Zen++ is used as a replacement of the standard library, -fno-rtti or something equivalent must be added to your compiler flags.

Use this library only if you feel like these drawbacks are justified for the project you're working on.

Installation and Usage

We support Meson and CMake. Currently, the preferred method for using these libraries is by downloading a recent tarball of the repository's source and checking in the sources into your project's version control system.

If you're building a library that uses Zen++ internally, it is highly recommended to define a custom Zen++ namespace. Doing so will avoid conflicts with dependencies that use a different version of these libraries. For instance, if your project has a namespace mylib, you would define the Zen namespace as mylib::zen.

Meson is the recommended choice for setting up your project. Download a tarball of this repository and drop the contents in subprojects/zen. Next, adjust the following example to match your project setup.

meson.build

project('myproject', 'cxx')

zen_proj = subproject('zen', default_options: ['namespace=mylib::zen'])
zen_dep = zen_proj.get_variable('zen_dep')

library('mylib', dependencies: zen_dep)

CMake is also supported, although we really recommend using Meson. CMake does not play nice with in-source subprojects because there's no elegant way to emulate Meson's default_options. Until we have figured out how to do it properly, you might want to use the following.

CMakeLists.txt

cmake_minimum_required(VERSION 3.10)

project(MyProject CXX)

# This will overwrite any value that might previously have been set.
set(ZEN_NAMESPACE mylib::zen CACHE INTERNAL "The Zen++ namespace this project will use" FORCE)

add_subdirectory(third_party/zen EXCLUDE_FROM_ALL)

add_library(mylib src/main.cc)

target_link_libraries(mylib zen)

Documentation

Documentation will soon be available on the official website. For now, you will have to consult the header files in zen/ to learn more. Alternatively, you can try to build the documentation locally using Doxygen.

License

This library is licensed under Apache 2.0 license. Briefly put, you are allowed to use this library commercially as long as you give due credit to the authors that put their time and energy in building this.

See the LICENSE file for more information.