The approach below isn't workable enough with the existing compiler extension capabilities, so using michaelwu's rust-bindgen fork is a lot less work.
A library to help ease the pain of calling C++ functions from Rust.
The basic idea is to generate a C-compatible library from a list of
C++ functions and structs to wrap, and then to use
rust-bindgen to generate the Rust
interface.
This is in contrast to trying to generate an exhaustive extern "C" interface
based on a C++ header file, or trying to link directly to C++ by parsing a
header file. The trade off is that this requires generating and compiling C++
code on every build (although there are lots of optimizations to be made).
It's currently in very early stages, but the eventual ideal is to have a rustc plugin generate the list of C++ calls by scraping the calls made from the Rust code.
Example usage is in the example directory, and can be run using cargo run.