-- | Check if argument is one of @\'a\', \'e\', \'i\', \'o\', \'u\', \'A\',
-- \'E\', \'I\', \'O\', \'U\'@.
isVowel :: (FromAscii a, Eq a) => a -> Bool
isVowel = isLowerVowel <||> isUpperVowel
isVowel :: (FromAscii a, Eq a) => a -> Bool
isVowel = isLowerVowel <||> isUpperVowel
isVowel = isLowerVowel <||> isUpperVowel