A Ruby program which checks if any anagram of a given string is a palindrome or not

anagram_palindrome.rb

#!/usr/bin/env ruby
# anagram_palindrome.rb

module AnagramPalindrome
    ASCII_COUNT = 256

    def anagram_of_palindrome?
        empty?

        histogram = Array.new ASCII_COUNT, 0
        self.length.times { |i| histogram[self[i].ord] += 1 }

        num_odds = histogram.count &:odd?

        num_odds <= 1
    end
end

class String
    include AnagramPalindrome
end

if __FILE__ == $0
    ARGV.each do |sentence|
        puts %Q{sentence "#{sentence}" is #{ sentence.anagram_of_palindrome? ? '' : 'not' } an anagram of palindrome}
    end 
end