Owing to limited resources, it is the intention that future
ruby-processing development will target ruby-2.2 (with likely
compatibility with MRI ruby-2.1). Any remaining backward compatibility
will be accidental. This change is obviously dependant on the release of
jruby-9.0.0.0 (a recent fix to jruby-9.0.0.0-SNAPSHOT has been shown to
work with the current version). But more significant changes will occur
(for ruby-processing) as and when processing-3.0 gets released.
Now that jruby-9.0.0.0.pre1 has been released you can experiment with
ruby-processing and ruby-2.2.0 syntax (works for me), if you want to run
sketches that require jruby-complete checkout
https://github.com/jashkenas/ruby-processing/tree/jruby-9000-pre
(branch). All comments suggestions gratefully received (please post
report issues/problems to github and not to stackoverflow!!!).