Internationalization Module User’s Guide : Chapter 3 Character and String Processing : Character Properties : Character Directionality
Character Directionality
All Unicode characters are assigned a directionality type in the Unicode Character Database. RWUCharTraits provides a BidirectionalCategory enum with values that identify the various directionality types, such as LeftToRight, RightToLeft, RightToLeftArabic, LeftToRightEmbedding, RightToLeftOverride, and so on. (See the documentation for RWUCharTraits in the SourcePro C++ API Reference Guide for a complete list of enumerated values.) The values in this enumeration correspond to the bidirectional category property codes defined in the Unicode Character Database, as described in Unicode Standard Annex #9, “The Bidirectional Algorithm”:
http://www.unicode.org/unicode/reports/tr9
The static method RWUCharTraits::getBidirectionalCategory() returns the value in the BidirectionalCategory enumeration identifying the directionality type associated with a given code point.