System.Text.RegularExpressions.RegexCharClass.IsWordChar C# (CSharp) Method

        internal static bool IsWordChar(char ch) {
            return CharInClass(ch, WordClass);
        }

 /*
  * Called by the implemenation of Go() to decide whether the pos
  * at the specified index is a boundary or not. It's just not worth
  * emitting inline code for this logic.
  */
 protected bool IsBoundary(int index, int startpos, int endpos)
 {
     return((index > startpos && RegexCharClass.IsWordChar(_runtext[index - 1])) !=
            (index < endpos && RegexCharClass.IsWordChar(_runtext[index])));
 }