public static bool IsNameStartChar(char c, char d)
 {
     if (CharHelper.IsHighSurrogate(c) && CharHelper.IsLowSurrogate(d))
     {
         int codepoint = CharHelper.ConvertToUtf32(c, d);
         return(codepoint >= 0x10000 && codepoint <= 0xeffff);
     }
     else
     {
         return(false);
     }
 }