Solidity 代码中未声明的标识符（字节；）

Question

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

// Import Interfaces
interface IUniversalRouter {
    function execute(
        bytes calldata commands,
        bytes[] calldata inputs,
        uint256 deadline
    ) external payable;
}

interface IPermit2 {
    function permit(
        address owner,
        address spender,
        address token,
        uint256 amount,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
}

interface IERC20 {
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    function approve(address spender, uint256 amount) external returns (bool);
    function balanceOf(address account) external view returns (uint256);
}

contract TokenSwapper {
    IUniversalRouter public universalRouter;
    IPermit2 public permit2;

    // Define Command Constants
    bytes1 public constant V3_SWAP_EXACT_IN = 0x00;

    // Events for tracking
    event SwapExecuted(
        address indexed user,
        address tokenIn,
        address tokenOut,
        uint256 amountIn,
        uint256 amountOutMin,
        uint256 deadline
    );

    constructor(address _universalRouter, address _permit2) {
        universalRouter = IUniversalRouter(_universalRouter);
        permit2 = IPermit2(_permit2);
    }

    function swapExactInputWithPermit(
        address tokenIn,
        address tokenOut,
        uint256 amountIn,
        uint256 amountOutMin,
        bytes calldata path,
        uint256 deadline,
        uint256 permitDeadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external {
        // Permit2 to approve UniversalRouter to spend Token A on behalf of the user
        permit2.permit(
            msg.sender,                // owner
            address(universalRouter),  // spender
            tokenIn,                   // token
            amountIn,                  // amount
            permitDeadline,            // deadline
            v, r, s                    // signature
        );

        // Construct the command and input data
        bytes memory commands = abi.encodePacked(V3_SWAP_EXACT_IN);

        // Input structure based on Dispatcher.sol:
        // (address recipient, uint256 amountIn, uint256 amountOutMin, bool payerIsUser, bytes path)
        bytes memory input = abi.encode(
            msg.sender,     // recipient
            amountIn,       // amountIn
            amountOutMin,   // amountOutMin
            true,           // payerIsUser
            path            // path
        );

        bytes; 
        inputsArray[0] = input;

        // Execute the swap via UniversalRouter
        universalRouter.execute{value: 0}(commands, inputsArray, deadline);

        // Emit event for tracking
        emit SwapExecuted(
            msg.sender,
            tokenIn,
            tokenOut,
            amountIn,
            amountOutMin,
            deadline
        );
    }

    receive() external payable {}
}

我正在尝试通过参与一个项目来学习 Solidity，并且我想使用 DEX 交换代币。我有该 DEX 和 Permit2 的合约地址，并且我编写了一个简单的智能合约来查看它是否有效，但我收到 inputArray[0] 的“未声明的标识符”错误，并且我不知道如何修复这。我将感谢您的帮助。

Answer 1

要修复

Undeclared identifier

错误，只需确保在

universalRouter.execute

中使用它之前声明并设置 inputArray 即可。查看添加的评论。

pragma solidity ^0.8.17;

contract TokenSwapper {
    IUniversalRouter public universalRouter;
    IPermit2 public permit2;
    bytes1 public constant V3_SWAP_EXACT_IN = 0x00;

    constructor(address _universalRouter, address _permit2) {
        universalRouter = IUniversalRouter(_universalRouter);
        permit2 = IPermit2(_permit2);
    }

    function swapExactInputWithPermit(
        address tokenIn,
        address tokenOut,
        uint256 amountIn,
        uint256 amountOutMin,
        bytes calldata path,
        uint256 deadline,
        uint256 permitDeadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external {
        permit2.permit(
            msg.sender,
            address(universalRouter),
            tokenIn,
            amountIn,
            permitDeadline,
            v, r, s
        );

        bytes memory commands = abi.encodePacked(V3_SWAP_EXACT_IN);
        bytes memory input = abi.encode(
            msg.sender,
            amountIn,
            amountOutMin,
            true,
            path
        );

// 用一个元素声明并初始化 inputArray

        bytes;

// 将编码后的输入数据分配给第一个元素

        inputsArray[0] = input;

        universalRouter.execute{value: 0}(commands, inputsArray, deadline);
    }
}