> Especially the possibility for Rust code to be called from foreign languages such as C very easily.

The second production deployment of Rust is a Ruby gem, written in C, that calls out to Rust. It's used in skylight.io, if you're curious.

> BTW is there an RFC on dynamically sized types?

IIRC, DST was before the RFC process even existed, it's just taken forever to implement. The Duke Nukem Forever of Rust. :) http://smallcultfollowing.com/babysteps/blog/2014/01/05/dst-... is what you want to read, IIRC.

> The second production deployment of Rust is a Ruby gem, written in C, that calls out to Rust. It's used in skylight.io, if you're curious.

Yep! I'm one of the authors of that project. The fact that Rust provides automatic memory cleanup and the attendant safety without runtime overhead (even ARC has non-trivial runtime overhead) was a huge win for us, as was the transparent FFI.

We were looking for a way to write fast code that was embeddable in a Ruby C extension with minimal runtime overhead and without a GC (two GCs in a single process is madness). We also wanted some guarantees that we wouldn't accidentally SEGV the Rails apps we were embedded in. Even last December, Rust was a clear winner for us.

We've been shipping Rust code to thousands of customers for many months, and given the language instability, it's worked really well for us.

Are there any open source libraries spun off from the Skylight agent? It would be nice to see some examples of production-quality Rust code.

A few:

* https://github.com/carllerche/hamcrest-rust - a (badly in need of more fleshing out) testing library * https://github.com/carllerche/nix-rust - bindings of Linux/OSX-specific APIs to Rust * https://github.com/carllerche/curl-rust - a binding of libcurl to Rust * https://github.com/carllerche/pidfile-rust - a library for using a pidfile for mutual exclusion across processes * https://github.com/carllerche/mio - a low-level IO library that attempts to implement an epoll-like interface across multiple platforms

> IIRC, DST was before the RFC process even existed, it's just taken forever to implement. The Duke Nukem Forever of Rust. :) http://smallcultfollowing.com/babysteps/blog/2014/01/05/dst-.... is what you want to read, IIRC.

Thanks for the info and the link!

Agreed. Two areas I can think of: 1. Rust library that is callable from Python. Many are using C/C++ for optimised Python program. 2. Able to create iOS framework library in Rust to be callable from Swift/Objective-C; similarly Rust library callable from Android NDK.