Predicate that checks if a Char is a digit.
Predicate that checks if a Char is a letter.
Predicate that checks if a Char is a letter or digit.
Predicate that checks if a Char is a lower case character.
Predicate that checks if a Char is an upper case character.
Predicate that checks if a Char is white space.
Module for
Charrelated predicates.