permutation adding uniq functionality

module Boolean 
end
TrueClass.send :include, Boolean
FalseClass.send :include, Boolean

true.is_a?(Boolean) #=> true

module ArrayExtensions
  def rpermute( possibilities = self.uniq.count, p_array = [], index = 0 )
    0.upto( possibilities - 1 ) do |i|
      p_array[ index ] = i
      if index < self.count - 1 # && !self.first.is_a?(Boolean)
        self.rpermute( possibilities, p_array, index + 1 )
      else
        result = Array.new
        0.upto( self.count - 1 ) do |j|
          result[ j ] = self[ p_array[ j ] ]
        end
       pp result
      end
    end
  end
end
module IntegerExtensions
  def truth_table_array
    ( 0...self ).map{ |i| [ true, false ] }.flatten
  end
end

Array.send :include, ArrayExtensions
Integer.send :include, IntegerExtensions

# no uniq pairs one can just count
a = [ 0, 1 ]
a.rpermute
[0, 0]
[0, 1]
[1, 0]
[1, 1]

a = [ 1, 2, 3 ]
a.rpermute
[1, 1, 1]
[1, 1, 2]
[1, 1, 3]
[1, 2, 1]
[1, 2, 2]
[1, 2, 3]
[1, 3, 1]
[1, 3, 2]
[1, 3, 3]
[2, 1, 1]
[2, 1, 2]
[2, 1, 3]
[2, 2, 1]
[2, 2, 2]
[2, 2, 3]
[2, 3, 1]
[2, 3, 2]
[2, 3, 3]
[3, 1, 1]
[3, 1, 2]
[3, 1, 3]
[3, 2, 1]
[3, 2, 2]
[3, 2, 3]
[3, 3, 1]
[3, 3, 2]
[3, 3, 3]

# only 2 possibilities from all uniq pairs  
number        = 0
number.truth_table_array.rpermute
no output

number        = 2
number.truth_table_array.rpermute
[true, true, true, true]
[true, true, true, false]
[true, true, false, true]
[true, true, false, false]
[true, false, true, true]
[true, false, true, false]
[true, false, false, true]
[true, false, false, false]
[false, true, true, true]
[false, true, true, false]
[false, true, false, true]
[false, true, false, false]
[false, false, true, true]
[false, false, true, false]
[false, false, false, true]
[false, false, false, false]