range-v3

Introduction to range-v3

Range-v3 is a comprehensive library for C++ that extends the capabilities of the Standard Template Library (STL). Designed for C++14, C++17, and C++20, it enhances the power of iterators and algorithms via a concept known as "composability". This library was pivotal in the development of a formal proposal for adding range support to the C++ standard library, which culminated in the inclusion of "The One Ranges Proposal" in C++20.

Key Features

1. Three Pillars: Views, Actions, and Algorithms

   • Algorithms: Range-v3 utilizes familiar STL algorithms but extends their functionality by allowing them to take ranges as parameters, in addition to iterators. This feature enhances convenience and readability.
   • Views: These are lazy, composable adaptations of ranges. They transform data as it is being iterated, providing a way to create pipelines of data transformations that are both efficient and expressive.
   • Actions: Differing from views, actions eagerly apply transformations to containers. They modify containers in-place and then return them for more processing.

2. Pipe Syntax

   • Range-v3 introduces a pipe syntax (rng | adapt1 | adapt2 | ...) to make the expression of transformations and operations on data clearer and more straightforward.

3. Broad Compiler Support

   • Range-v3 is supported by several major compilers, including Clang, GCC, and MS Visual Studio, although specific flags and versions are necessary for optimal function due to its strict conformance requirements.

Documentation and Resources

Despite the library's power, its documentation is acknowledged to be somewhat incomplete. However, users can find resources and usage guides through various talks, blog posts, and formal proposals related to the library's development:

• Video Resource: Eric Niebler's talk at CppCon 2015.
• Articles and Blogs: Posts detailing various aspects of range-v3, including range comprehensions and iterator discussions.

Development Status

The library is stable and well-tested, although it is still evolving and generally does not guarantee backward compatibility. However, components within the ranges::cpp20 namespace are expected to remain stable.

Licensing

Range-v3 is primarily licensed under the Boost Software License, with some parts derived from other notable projects like Alex Stepanov's Elements of Programming and SGI STL.

Building range-v3

Range-v3 can be integrated into projects using several tools, such as:

• vcpkg: A dependency manager that allows you to install range-v3 easily.
• Conan: Another dependency manager, particularly handy for CMake integration.
• build2: A combined dependency manager and build system for those looking to work with or utilize range-v3 in their projects.

Each tool offers specific instructions and configurations to facilitate the integration of range-v3 into users' projects, catering to different development environments and preferences.

Conclusion

Range-v3 represents a significant advancement in the flexibility and power of C++ programming by extending the traditional STL capabilities with ranges that are more expressive and more intuitive to work with. By enriching C++ with these capabilities, range-v3 aids developers in writing clearer, more concise, and functional code.