code: private static int _escape (final StringBuilder out, final char ch, final int pos)
    {
      if (isEscapeChar (ch))
      {
        out.append (ch);
        return pos + 1;
      }
      out.append ('\\');
      return pos;
    }
docs: Processed the given escape sequence.
  
  @param out
  The StringBuilder to write to.
  @param ch
  The character.
  @param pos
  Current parsing position.
  @return The new position.