boost::text::bidi_property
// In header: <boost/text/bidirectional_fwd.hpp> enum bidi_property { L, R, EN, ES, ET, AN, CS, B, S, WS, ON, BN, NSM, AL, LRO, RLO, LRE, RLE, PDF, LRI, RLI, FSI, PDI };
The bidirectional algorithm properties defined by Unicode.