format
List of 17
$ alnum :Classes 'character_class', 'regex' chr "[:alnum:]"
$ alpha :Classes 'character_class', 'regex' chr "[:alpha:]"
$ letter :Classes 'character_class', 'regex' chr "[:alpha:]"
$ blank :Classes 'character_class', 'regex' chr "[:blank:]"
$ cntrl :Classes 'character_class', 'regex' chr "[:cntrl:]"
$ digit :Classes 'character_class', 'regex' chr "[:digit:]"
$ number :Classes 'character_class', 'regex' chr "[:digit:]"
$ graph :Classes 'character_class', 'regex' chr "[:graph:]"
$ lower :Classes 'character_class', 'regex' chr "[:lower:]"
$ print :Classes 'character_class', 'regex' chr "[:print:]"
$ punct :Classes 'character_class', 'regex' chr "[:punct:]"
$ space :Classes 'character_class', 'regex' chr "[:space:]"
$ upper :Classes 'character_class', 'regex' chr "[:upper:]"
$ xdigit :Classes 'character_class', 'regex' chr "[:xdigit:]"
$ single_quote:Classes 'character_class', 'regex' chr "'"
$ double_quote:Classes 'character_class', 'regex' chr "\""
$ quote :Classes 'character_class', 'regex' chr "'\""