Foreword

jank is a personal creation made public. It’s a passion project which aspires to push the boundaries of two languages very dear to me: C++ and Clojure. These two languages could not be further apart, in their syntax, paradigms, culture, adoption, and typical use cases. Still, I aim to bind them.

jank is currently alpha quality software. Most importantly, that means that you would be crazy to ship it into production for anything that matters. More specifically, it means that jank, and its related programs, will crash, leak memory, provide incorrect results, and in general surprise, confound, and frustrate until we can implement all remaining pieces and iron out all remaining bugs. I need your help with this.

Before jank, achieving this level of seamless C++ interop, with JIT (just in time) compiled C++, and full AOT (ahead of time) compilation support had never been done, from any dynamic language. Swift has come closest, though it’s not dynamically typed and it lacks an official JIT compiler. Cppyy, for Python, strives to compete, but it lacks AOT compilation support. Because of this trail blazing, we have faced many bugs in Clang. Clang is the main challenge for both compile-time performance and overall memory usage. This continues to be a limiter for jank’s success, due to the size and complexity of the Clang code base and my limited time. To ensure jank’s success, this challenge will need to be tackled directly, most likely by finding and employing a part-time Clang developer. If you are able to help with this, please reach out.

Moving on.

The performance of jank, during this alpha stage, will be quite bad. Depending on the benchmark, you might find jank to be 2x or even 10x slower than Clojure JVM. Maybe more.

Do not be concerned by this. I am not concerned by this.

I have not had the luxury to focus on performance much beyond some early design decisions. Clojure JVM, aside from leaning on the JVM for much of its performance, is doing many more optimizations than jank is currently doing. A lot of functionality, such as the GC (BDWGC), sorted containers, and others are currently placeholder. What’s most important is that jank works and that it’s correct. Once we achieve that, I will endeaver to show that jank can be the fastest Clojure dialect around. Right now, that is not a priority, no matter how much you may want it to be.

Lastly, the Clojure community is empowered by backward compatibility. I respect and appreciate this goal for both Clojure and jank. I will be codifying stable APIs for embedding jank, ensuring the stability of jank’s special forms, developing an integrated build system to improve the longevity of jank libraries which wrap native libraries, and pursuing binary compatibility as much as the native world and all of its quirks allows. However, during the alpha release stage, and until we have our first production release, anything goes.

Now, install jank. Build some software. Report all of your bugs on Slack or Github! Engage in the community. Work with us as we stabilize and forge this language into what others in the future will know it to be.

Jeaye