public void put(String name,Value v) throws SimPLException
	{
		Env cur = this;
		boolean flag = true;
		while(cur!=null)
		{
			if(cur.map.containsKey(name))
			{
				cur.map.put(name, v);
				flag = false;
				break;
			}
			cur = cur.parent;
		}
		if(flag)throw new SimPLException(name +" not existed",errortype.runtime_error);
	}