Blockchain Solidity Nested_mapping

refer to: kimi,
https://ethereum.stackexchange.com/questions/42272/is-it-possible-to-assign-a-map-as-a-mappings-value

三重mapping的例子：

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.13;

contract TripleNestedMapping {
   // 这样声明
   mapping(string => mapping(uint256 => mapping (uint256 => bool) )) users_and_passwords;

   function setLogin(string calldata _name, uint256 _password, uint256 _pin) public {
     // 注意不能这样弄。因为 无法在function中创建动态的mapping
     //mapping(uint256 => mapping(uint256 => bool) ) memory pins ;
     //mapping(uint256 => bool) memory isCanLogin;
     //isCanLogin[_pin] = true;
     //pins[_password] = isCanLogin;
     //users_and_passwords[_name] = pins;

     // 只能这样弄。因为调用的是 contract 的member
     users_and_passwords[_name][_password][_pin] = true;
   }

   function isLoggedIn(string calldata _name, uint256 _password, uint256 _pin) public view returns (bool) {

     return users_and_passwords[_name][_password][_pin];
   }

}