IN_RANGE Description Checks if the value x is within the inclusive range [lo, hi].
IS_ALPHA Description Checks if the given character c is an ASCII alphabet.
IS_CAPS_ALPHA Description Checks if the given character c is an uppercase ASCII alphabet.
IS_DIGIT Description Checks if the given character c is an ASCII digit.
IS_SPACE Description Checks if the given character c is a whitespace character.
IS_XDIGIT Description Checks if the given character c is a hexadecimal digit.