MacPorts and Ruby environments

Generally, The most easy way to install ruby on Mac OS is to use MacPorts. I read the installation guide, then I do 3 operations:

1. Install "Xcode Developer Tools" from Mac OS X installation DVD
2. Download MacPorts-1.9.1-10.6-SnowLeopard.dmg
3. Install MacPorts from MacPorts-1.9.1-10.6-SnowLeopard.dmg

Then let's check the ruby environments MacPorts is managing.

$ sudo port list | grep lang/.*ruby
jruby                          @1.4.0          lang/jruby
ruby                           @1.8.7-p249     lang/ruby
ruby186                        @1.8.6-p388     lang/ruby186
ruby19                         @1.9.1-p378     lang/ruby19

As you see, Ruby 1.8.6, 1.8.7 and 1.9.1 are up to date. But 1.9.2 is not available, and JRuby is NOT 1.5.x.
I decide to install ruby 1.8.7, ruby 1.9.1 and JRuby 1.4.0.

$ sudo port install ruby
$ sudo port install ruby19
$ sudo port install jruby