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我正在浏览 HomeKit 目录中的旧代码：当我遇到一个表达式时，创建家庭、配对和控制配件以及设置触发器

.KeyPathExpressionType

我不知道是什么

.

在

.KeyPathExpressionType

是指在左侧

.

当我搜索谷歌并堆栈溢出“KeyPathExpressionType”时，我什么也没找到。这是一样的

.ConstantValueExpressionType

我什么也没找到。

这些相等比较中的每一个

comparison.leftExpression.expressionType == .KeyPathExpressionType

和

comparison.rightExpression.expressionType == .ConstantValueExpressionType

在下面的代码中，生成一条错误消息，内容为：

二元运算符“==”不能应用于“NSExpression.ExpressionType”和“_”类型的操作数

extension NSPredicate {

    /**
        Parses the predicate and attempts to generate a characteristic-value `HomeKitConditionType`.

        - returns:  An optional characteristic-value tuple.
    */
    private func characteristic() -> HomeKitConditionType? {
        guard let predicate = self as? NSCompoundPredicate else { return nil }
        guard let subpredicates = predicate.subpredicates as? [NSPredicate] else { return nil }
        guard subpredicates.count == 2 else { return nil }

        var characteristicPredicate: NSComparisonPredicate? = nil
        var valuePredicate: NSComparisonPredicate? = nil

        for subpredicate in subpredicates {
            if let comparison = subpredicate as? NSComparisonPredicate, comparison.leftExpression.expressionType == .KeyPathExpressionType && comparison.rightExpression.expressionType == .ConstantValueExpressionType {
                switch comparison.leftExpression.keyPath {
                    case HMCharacteristicKeyPath:
                        characteristicPredicate = comparison

                    case HMCharacteristicValueKeyPath:
                        valuePredicate = comparison

                    default:
                        break
                }
            }
        }

        if let characteristic = characteristicPredicate?.rightExpression.constantValue as? HMCharacteristic,
            characteristicValue = valuePredicate?.rightExpression.constantValue as? NSCopying {
                return .Characteristic(characteristic, characteristicValue)
        }
        return nil
    }

更换时错误消失

comparison.leftExpression.expressionType == .KeyPathExpressionType

和

comparison.leftExpression.expressionType.rawValue == NSExpression.ExpressionType.keyPath.rawValue

和

comparison.rightExpression.expressionType == .ConstantValueExpressionType

和

comparison.rightExpression.expressionType.rawValue == NSExpression.ExpressionType.constantValue.rawValue

这个对吗？谁能告诉我这个问题的启发？

4

1 回答 1

1

该代码是过时的 Swift 2 代码。

替换.KeyPathExpressionType为.keyPath和.ConstantValueExpressionType_.constantValue

类型是NSExpression.ExpressionType，请阅读文档

于 2019-05-22T12:52:26.357 回答