/// <summary>
 /// 复制成生一个新结点
 /// </summary>
 /// <param name="source"></param>
 /// <param name="desc"></param>
 public static void CopyTo(this IErlangElement source, IErlangElement desc)
 {
     desc.Context = source.Context;
     desc.Elements = source.Elements;
     desc.Index = source.Index;
     desc.GroupName = source.GroupName;
     desc.Parent = source.Parent;
     desc.Next = source.Next;
     desc.Prev = source.Prev;
     desc.Index = source.Index;
     desc.Elements = source.Elements;
     desc.Line = source.Line;
 }
 /// <summary>
 /// 所有IErlangElement都是ErlangElemenet对象.
 /// </summary>
 /// <param name="elem"></param>
 /// <returns></returns>
 public bool IsTypeOf(IErlangElement elem)
 {
     return true;
 }