# File lib/facet/soundex.rb, line 67
    def soundex_str(str)
      return nil if str.empty?
  
      str = str.upcase
      last_code = get_code(str[0,1])
      soundex_code = str[0,1]
  
      for index in 1...(str.size) do
        return soundex_code if soundex_code.size == 4
  
        code = get_code(str[index,1])
        
        if code == "0" then
          last_code = nil
        elsif code == nil then
          return nil
        elsif code != last_code then
          soundex_code += code
          last_code = code        
        end 
      end # for

      
      return soundex_code + "000"[0,4-soundex_code.size]
    end