Case is a property of some alphabets in which different characters are considered to be variants of the same letter. Unicode case mappings are described in Section 5.18 of the Unicode standard:

RWUCharTraits provides the static methods RWUCharTraits::isLower(), RWUCharTraits::isTitle(), and RWUCharTraits::isUpper(). These methods return true if a given RWUChar32 represents a code point for a lowercase, titlecase, or uppercase letter, respectively.

Static methods RWUCharTraits::toLower(), RWUCharTraits::toTitle(), and RWUCharTraits::toUpper() are also provided, which perform simple case conversions. An equivalent letter in the desired case is returned if such a mapping exists in the character database. If the letter has no equivalent in the desired case, the character itself is returned.