Functional programming in C++
The purpose of this library is to exercise an approach to functional programming in C++ on top of the existing std C++ vocabulary types (such as std::expected and std::optional), with the aim of eventually extending the future versions of the C++ standard library with the functionality found to work well.
The approach is to take the existing types in the C++ standard library (when appropriate) and add both syntax and operations which are useful in writing functional style programs.
This library requires a very modern implementation of C++ library which implements monadic operations in optional and expected, as defined in ISO/IEC 14882:2023. Currently, such a library is provided with gcc 13, which is the recommended compiler for this project. A suggested approach to access this version of the compiler (when it is not available in the operating system) is to use containers when working with this project.
In this project, 100% tests coverage does not actually mean much, because the most useful tests cases are around compile-time language elements, such as overload resolution, built-in conversions etc. Any meaningful tests must execute the same set of functions in many, subtly different ways, rather than simply execute each function and branch at least once.
Gašper Ažman for providing the inspiration in "(Fun)ctional C++ and the M-word"