> I've just got my hands on the latest Mastering Regular Expressions.
> I want to play with some of the clever stuff (eg lookbehinds) in
> ruby.  I'm running OS X on my desktop, and my ruby is compiled from
> MacPorts.  There's an oniguruma port, but does anyone know how to
> recompile ruby to use it?  Is there a command line switch I can pass
> to the port command?

I've not used MacPorts, but, it is pretty straight forward to build it by
hand:

~/Desktop $ tar xzf ruby-1.8.5.tar.gz
~/Desktop $ tar xzf onigd2_5_8.tar.gz

~/Desktop $ cd oniguruma/
~/Desktop/oniguruma $ ./configure --with-rubydir=~/Desktop/ruby-1.8.5
~/Desktop/oniguruma $ make 185
~/Desktop/oniguruma $ cd ..

~/Desktop $ cd ruby-1.8.5
~/Desktop/ruby-1.8.5 $ ./configure --prefix=/opt/ruby/v1.8.5-oniguruma
~/Desktop/ruby-1.8.5 $ make
~/Desktop/ruby-1.8.5 $ sudo make install

~/Desktop/ruby-1.8.5 $ /opt/ruby/v1.8.5-oniguruma/bin/ruby -v
ruby 1.8.5 (2006-08-25) [powerpc-darwin8.8.0]
~/Desktop/ruby-1.8.5 $ /opt/ruby/v1.8.5-oniguruma/bin/ruby -e "put s
Regexp::ENGINE"
Oniguruma