Giuseppe Bilotta wrote:

> I have this library which I would like to use with Ruby. How do I do 
> it?

Tom has already mentioned Ruby/DL in a separate response. Two other 
choices you might want to consider are Joel VanderWerf's CGenerator 
module (http://redshift.sourceforge.net/cgen) and SWIG 
(http://www.swig.org). If it's straight C code in the library I think 
Ruby/DL might be a good choice and CGenerator possibly better; I haven't 
used either of them. If you're dealing with C++ code, I think SWIG might 
be the right choice.

I'm putting together a presentation on SWIG and Ruby for the Ruby 
conference in November, and I'd like to (at least briefly) touch on some 
of the alternatives (like Ruby/DL and CGenerator). I might also throw in 
  a few words about things that don't actually exist yet for Ruby, but 
which could be done (e.g. a Ruby equivalent of Boost::Python). If you 
run across any others I'd like to hear about them.