-isControl, isPrint, isSpace, isUpper,
- isLower, isAlpha, isDigit, isOctDigit, isHexDigit, isAlphaNum
- :: Char -> Bool
+-- | Selects control characters, which are the non-printing characters of
+-- the Latin-1 subset of Unicode.
+isControl :: Char -> Bool
+
+-- | Selects printable Unicode characters
+-- (letters, numbers, marks, punctuation, symbols and spaces).
+isPrint :: Char -> Bool
+
+-- | Selects white-space characters in the Latin-1 range.
+-- (In Unicode terms, this includes spaces and some control characters.)
+isSpace :: Char -> Bool
+
+-- | Selects alphabetic Unicode characters (letters) that are not lower-case.
+-- (In Unicode terms, this includes letters in upper and title cases,
+-- as well as modifier letters and other letters.)
+isUpper :: Char -> Bool
+
+-- | Selects lower-case alphabetic Unicode characters (letters).
+isLower :: Char -> Bool
+
+-- | Selects alphabetic Unicode characters (letters).
+isAlpha :: Char -> Bool