Update: 6:45 p.m. GMT, As far as I know, you can just install the binary package of RubyCocoa and the default Apple installation of Ruby will be sufficient to make this app work.
Update: 6:19 p.m. GMT, I fixed a bug in the checker. Get the new one as usual from the Box widget.
Application icon credits: rox-ruby
I have uploaded a little Regular Expression checker I made in RubyCocoa(see RegEx.dmg in my Box widget to your left). I only have an Intel Mac to test it on, so I have no idea whether it will run correctly on PPC Macs. The code is licensed under the GPLv2. It may be the case the that you need RubyCocoa properly installed to run this app. See my post on installing BioRuby for Mac OS X for a link to Dan Benjamin’s instructions on updating your Ruby installation(adapt these instructions accordingly for Ruby 1.8.5). For installing RubyCocoa under Ruby 1.8.5, if memory serves, these commands (once you extract the files from the archive and go to the to-level directory of RubyCocoa),
$ ruby install.rb –help # print all options
$ ruby install.rb config
$ ruby install.rb setup
from this website are the key instructions. You may have to prefix sudo in one of the above three commands.
11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO
WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.
EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR
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PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
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AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU
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FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF
SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH