DeclarationError:未定义的标识符-solidity

Question

我收到了一条非常奇怪的错误消息——DeclarationError：未定义的标识符。

它在我所有的函数中都给出了这个，我不知道为什么。有人能告诉我发生了什么事吗？

我正在使用以太坊、Solidity和Openzepellinn来完成这项工作，但为了能够完成下一步，我需要我的界面在没有任何这些错误的情况下工作。

请参阅下面的代码

pragma solidity ^0.8.0;

interface AggregatorV3Interface {
function decimals() external view returns (uint8);
function description() external view returns (string memory);
function version() external view returns (uint256);
// getRoundData and latestRoundData should both raise "No data present"
// if they do not have data to report, instead of returning unset values
// which could be misinterpreted as actual reported values.
function getRoundData(uint80 _roundId)
external
view
returns (
uint80 roundId,
int256 answer,
uint256 startedAt,
uint256 updatedAt,
uint80 answeredInRound
);
function latestRoundData()
external
view
returns (
uint80 roundId,
int256 answer,
uint256 startedAt,
uint256 updatedAt,
uint80 answeredInRound
);
}
/**
* THIS EXAMPLE USES UN-AUDITED CODE.
* Network: Kovan
* Base: BTC/USD
* Base Address: 0x6135b13325bfC4B00278B4abC5e20bbce2D6580e
* Quote: EUR/USD
* Quote Address: 0x0c15Ab9A0DB086e062194c273CC79f41597Bbf13
* Decimals: 8
*/
contract PriceConverter {
address public priceSource;
address public quote;
uint8 private decimals;



uint256 public fallbackPrice;
event FallbackPrice(
uint80 roundId, 
int256 answer,
uint256 startedAt,
uint256 updatedAt, 
uint80 answeredInRound
);
constructor(address _priceSource, address _quote, uint8 _decimals) public {
priceSource = _priceSource;
quote  = _quote;
decimals =  uint8(10 ** uint8(_decimals));

}
function latestRoundData() public view
returns 
(uint80 roundId,
int256 answer,
uint256 startedAt,
uint256 updatedAt, 
uint80 answeredInRound
)

{

require(decimals > uint8(0) && decimals <= uint8(18), "Invalid _decimals");

( , int256 basePrice, , , ) = address(priceSource).latestRoundData();
uint8 baseDecimals = address(priceSource).decimals();
basePrice = scalePrice(basePrice, baseDecimals, decimals);
( , int256 quotePrice, , , )  = address(quote).latestRoundData();
uint8 quoteDecimals = address(quote).decimals();
quotePrice = scalePrice(quotePrice, quoteDecimals, decimals);
return basePrice * decimals / quotePrice;


}

function updateFallbackPrice() public {
(
uint80 roundId, 
int256 answer,
uint256 startedAt,
uint256 updatedAt, 
uint80 answeredInRound
) = priceSource.latestRoundData();
if (answer > 0) {
fallbackPrice = uint256(answer);
emit FallbackPrice(roundId,answer,startedAt,updatedAt,answeredInRound);
}
}

function scalePrice(int256 _price, uint8 _priceDecimals, uint8 _decimals)
internal
pure
returns (int256)
{
if (_priceDecimals < _decimals) {
return _price * int256(10 ** uint256(_decimals - _priceDecimals));
} else if (_priceDecimals > _decimals) {
return _price / int256(10 ** uint256(_priceDecimals - _decimals));
}
return _price;
}
} ```

Also i added screenshot of what it looks like on remix IDE


[1]: https://i.stack.imgur.com/e00dC.png

Answer 1

第一个错误，这是您的构造函数

constructor(address _priceSource, address _quote, uint8 _decimals) public {
priceSource = AggregatorV3Interface(_priceSource);
quote  = ERC20(_quote);
decimals = uint8 (_decimals);

}

使用类型uint8初始化_decimals，然后再次将其转换为uint8，这不是必需的

在函数中，您使用的是仅在构造内部初始化的_decimals，但您将其传递给decimals的值，您必须使用它而不是_decimals