CLIPSJNI via JRuby

clips_jni.rb

# 1) Install JRuby
#      http://jruby.org/
# 2) Download CLIPSJNI 6.30
#      http://sourceforge.net/projects/clipsrules/files/CLIPS/
# 3) Put this file in the CLIPSJNI folder, then:
#
#      % cd [CLIPSJNI folder]
#      % jruby clips.rb
#
# == Notes
#
# The details of #3 are significant.  I found that the dynamic library for
# CLIPSJNI must be in the working directory for jruby to properly load
# Environment.  That means one of these files:
#
# * libCLIPSJNI.jnilib (mac)
# * CLIPSJNI.dll (windows, I think)
#
# What's really going on is that the dynamic library must be on the
# 'java.library.path'.  It's not enough to be on the jruby LOAD_PATH.
#
# So lets say you wanted:
#
#   clips.rb
#   lib/
#     CLIPSJNI.jar
#     libCLIPSJNI.jnilib
#
# You would need:
#    
#   % jruby -Ilib -J-Djava.library.path=lib clips.rb
#
# Where -Ilib sets the jruby LOAD_PATH and -J-D... sets the java.library.path.
# I don't know how to set the java library path in code, but there must be a
# way.

include Java
require 'CLIPSJNI.jar'
include_class 'CLIPSJNI.Environment';

clips = Environment.new
clips.build %q{ (defrule red-light (light red) => (printout t "Stop" crlf))   }
clips.build %q{ (defrule green-light (light green) => (printout t "GO" crlf)) }
clips.assert_string "(light green)"

clips.run  # should printout 'GO'