public String toString()
	{
		if(etype!=null)
		{
			switch(etype)
			{
			case synatax_error:
				return "Syntax Error!"+msg;
			case type_error:
				return "Type Error!"+msg;
			case runtime_error:
				return "Runtime Error!"+msg;
			}
		}
		return "no type";
	}