Character type functions

&reftitle.intro; The functions provided by this extension check whether a character or string falls into a certain character class according to the current locale (see also setlocale). When called with an integer argument these functions behave exactly like their C counterparts from ctype.h. When called with a string argument they will check every character in the string and will only return &true; if every character in the string matches the requested criteria. When called with an empty string the result will always be &true;. Passing anything else but a string or integer will return &false; immediately.