Well, last guess before I head to bed:

In "mylib.rb":

begin
	require "mylib_impl_c" # Attempts to load the C shared library.
rescue LoadError
	require "mylib_impl_rb" # Falls back to the ruby implementation.
end

Yay for gracefully degrading functionality. Or performance, for that matter. 
Sprinkle with configuration parameters to let user determine at runtime which 
backend to use to taste.

David Vallner

Da Streda 08 Februr 2006 20:58 Patrick Gundlach napsal:
> Hi,
>
> I have a simple library, one in a pure ruby version and one in a
> ruby/c version (which is quicker). I would like to distribute both and
> let the user decide (by checking whether a c library is available)
> which version to install. What would a clever way to accomplish that?
> Should I make the decision when running extconf.rb? Any hints?
>
> Patrick
>
> (the directory structure so far)
>
> rb/mylib.rb
>
> c/mylib.rb
>  /mylib_base.c
>  /extconf.rb
>
> both should be used by require 'mylib' or alike.