string_maybe_empty                                                                                                                                                                                                                                                                                                                              
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                     '                                                                                                                                                                                                                                                                                   '
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                       character                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                     "                                                                                                                                                                                                                                                                                   "
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                       character                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
          string_non_empty                                                                                                                                                                                                                                                                                                                                
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                     '                                                         character                                                                                                                                                                 '                                                
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                                                                                                                                                                                                                                                                                                          
                                                                     "                                                         character                                                                                                                                                                 "