23rd/range-v3

Range-v3 is a C++ library that lets programmers chain data-transformation operations together in a clean, readable way, similar to how you might pipe commands in a Unix terminal. Instead of writing nested function calls or temporary variables to sort, filter, and transform collections of data, you can write a single expression that reads left to right. At its core, the library extends C++'s existing Standard Template Library by building an abstraction layer on top of iterators (the mechanism C++ already uses to step through collections). It introduces three main tools: Views, which adapt data lazily (meaning transformations only happen as needed, not upfront), Actions, which eagerly modify containers in place, and familiar Algorithms that now accept entire ranges directly. The pipe syntax, writing something like data | filter | sort, makes the code terse and easy to follow. This library is primarily for C++ developers working in C++14, 17, or 20. A practical use case: imagine you have a list of user records and need to filter out inactive users, sort by name, then extract just the email addresses. With this library, that chain of operations becomes a single readable pipeline rather than several discrete steps with intermediate variables. What makes this project historically significant is that it became the basis for the ranges feature officially added to the C++20 standard. The proposals that grew out of this library were merged into the C++ working drafts in 2018, meaning this code effectively shaped the future direction of the language itself. The project is described as fairly stable and well-tested, though the author notes the documentation is incomplete. The code is expected to evolve without backward compatibility guarantees, with one exception: components in a specific namespace called ranges::cpp20 are meant to stay stable and align with the standardized version. It supports recent versions of Clang, GCC, and Visual Studio.