+/// return true if a unicode char is a numeral.
+bool isNumber(char_type c);
+
+/// return true if a unicode char has the direction attribute
+/// European Number Separator [ES]
+bool isEuropeanNumberSeparator(char_type c);
+
+/// return true if a unicode char has the direction attribute
+/// European Number Terminator [ET]
+bool isEuropeanNumberTerminator(char_type c);