The jruby_visualizer gem takes as input Ruby code and visualizes artifacts of JRuby's compiler/interpreter tool chain. This includes

• the Abstract Syntax Tree (AST)
• the Intermediate Representation (IR)
• the execution of compiler passes on IR
• a visualization for the Control Flow Graphs (CFGs) on JRuby Scopes

You can install this visualizer as gem into your jruby environment:

1. Clone the repository $ git clone https://github.com/jruby/jruby-visualizer.git
2. Build the gem $ rake build
3. Install the gem $ jruby -S gem install --local pkg/jruby_visualizer-0.1.gem

Either

1. call into the library

$ ./lib/jruby_visualizer.rb                             
RuntimeError: No ruby input for the JRuby Visualizer
  Usage: 
    ./lib/jruby_visualizer.rb "def foo; 42; end; foo"
  or
    ./lib/jruby_visualizer.rb foo.rb
  (root) at ./lib/jruby_visualizer.rb:15

This is also possible with the following command, to visualize foo.rb:

$ jruby -Ilib ./bin/jruby_visualizer foo.rb

2. Execute the installed binary

$ jruby_visualizer foo.rb

3. Use the visualizer as gem in your jruby code

#!/usr/bin/env jruby

require 'jruby_visualizer'

JRubyVisualizer::visualize('def bar; puts "spam HAM"; end; bar')