map_product_strings.rb

def map_product_strings(prod_val, &block)                                                                                               
  # product hash -> product hash with strings changed through block                                                                     
  case prod_val                                                                                                                         
  when Hash                                                                                                                             
    Hash[prod_val.map {|key, val| [key, map_product_strings(val, &block)]}]                                                             
  when Array                                                                                                                            
    prod_val.map { |v| map_product_strings(v, &block) }                                                                                 
  when String                                                                                                                           
    yield prod_val                                                                                                                      
  else                                                                                                                                  
    prod_val                                                                                                                            
  end                                                                                                                                   
end