Add implementation of product

Ruby 1.8.6 doesn't have Array#product, so add it

1 files changed, 11 insertions, 0 deletions

diff --git a/state.rb b/state.rb
index 011567b..b69421a 100644
--- a/state.rb
+++ b/state.rb
@@ -5,6 +5,17 @@ Author: Casey Dahlin <cjdahlin@ncsu.edu>
 =end
 require 'set'
 
+unless Array.instance_methods.include? "product"
+	class Array #:nodoc:
+		def product(*others)
+			return self.map{ |x| [x] } if others.size == 0
+			self.map do |x|
+				(others[0].product(*others[1..-1])).map{ |y| [x] + y }
+			end.inject([]){ |x,y| x+y }
+		end
+	end
+end
+
 module UpState
 
 # Occurs when the state machine becomes inconsistent