CppCon 2016

The Clang project has been working on Modules in one form or another for many years. It started off with C and Objective-C many years ago. Today, we have a C++ compiler that can transparently use C++ Modules with existing C++ code, and we have deployed that at scale. However, this is very separate from the question of how to integrate a modular compilation model into the language itself. That is an issue that several groups working on C++ have been trying to tackle over the last few years.

Based on our experience deploying the core technology behind Modules, we have learned a tremendous amount about how they interact with existing code. This has informed the particular design we would like to see for C++ Modules, and it centers around incremental adoption. In essence, how do we take the C++ code we have today, and migrate it to directly leverage C++ Modules in its very syntax, while still interacting cleanly with C++ code that will always and forever be stuck in a legacy mode without Modules.

In this talk we will present our ideas on how C++ Modules should be designed in order to interoperate seamlessly with existing patterns, libraries, and codebases. However, these are still early days for C++ Modules. We are all still experimenting and learning about what the best design is likely to be. Here, we simply want to present a possible and still very early design direction for this feature.