I just used JRuby FFI to implement a native x86-64 debugger on WinAPI; we had x86 working for a long time on Win32, Linux, and OSX using MRI, and JRuby was actually the only way to get around LP64 issues with MRI. JRuby has been a compat and native code win for us; it is a better platform for accessing C code than MRI Ruby is.
That's great to hear! Given that FFI is intended to work across all Ruby impls, I wish there were more attention paid to using FFI instead of C extensions. I will admit there are some usability problems, especially around cross-platform struct mapping, but the resulting libraries are vastly easier to deal with than a bunch of grotty Ruby C API code.
Huge fan of FFI (I use it to wrap/test all my shared libraries, mysql ext, etc..), but the problem of cross platform compilation still exists. I write a shared library and an FFI interface, but packaging it for use on Windows/*nix is still a pain (for compilation during install). Is there anything that solves for compilation across implementations and platforms? (FFI makes the interface simple after that)
I don't think we should have to sign up for coupling with a specific Ruby's runtime internals just to get cross-platform compilation of a shared library. For whatever it's worth, even autoconf can be made to work cross-platform.
Yeah, for that I don't have a solution. It seems like there ought to be a way to have FFI libraries bring along the lib they need and compile it right there, but portable C libs are still a bitch to manage across platforms no matter what you do. I hate to say it, but JVM libraries have a huge advantage here; most JRuby-specific libs that ship a jar file just work on any platform with no recompile and no portability issues. Hard to beat that :(
JRuby's FFI implementation is great, but I've had about as much success with MRI, so I test my FFI libs on MRI 1.8.7, 1.9.2 and the latest JRuby. I'm looking forward to the day when Rubinius' FFI converges with the other implementations.