调用中缺少参数＃1的参数

I have a lazy parameter that I'm attempting to call a helper function in:

我有一个懒惰的参数，我试图调用辅助函数：

class ColumnNode: SCNNode {

    lazy var upperColumnNode: SCNNode = {
        return buildColumPart()
    }()

    func buildColumPart() -> SCNNode {
        var node = SCNNode()
        ...
        return node
    }
}

Unfortunately on line return buildColumPart() I am getting:

不幸的是在线返回buildColumPart（）我得到：

Missing argument for parameter #1 in call

What exactly does this mean and how do I fix it?

这究竟是什么意思，我该如何解决？

1 个解决方案

#1

You need to use self to access instance methods in lazy properties:

您需要使用self来访问延迟属性中的实例方法：

class ColumnNode: SCNNode {

    lazy var upperColumnNode: SCNNode = {
        return self.buildColumPart()
    }()

    func buildColumPart() -> SCNNode {
        var node = SCNNode()
        ...
        return node
    }
}

Interestingly enough, the reason it's complaining about parameter #1 is that instance methods are actually class methods that take an instance as a parameter and return a closure with the instance captured - instead of self.buildColumPart(), you could instead call buildColumPart(self)().

有趣的是，它抱怨参数＃1的原因是实例方法实际上是类方法，它将实例作为参数并返回一个捕获实例的闭包 - 而不是self.buildColumPart（），你可以改为调用buildColumPart（self ）（）。