英文:
A generic which is value is a collection
问题
我希望能够创建一个具有通用类型的类，并创建一个扩展，用于处理通用类型为Dictionary的情况。
例如：
public final class AtomicCollection<WrappedValue> {
}
我想要能够实现所有Dictionary/Array/Set具有的方法，例如 func removeAll()。
我尝试使用扩展来实现：
extension AtomicCollection where WrappedValue == Dictionary {
}
问题是，我收到以下错误：
Reference to generic type 'Dictionary' requires arguments in <...>
这将导致我需要提及Dictionary的Key和Value类型，Element是Array的类型等。
我希望能够为所有的Dictionary、Array和Set创建通用约束。
有什么想法？
英文:
I wish to be able to create a class with a generic type, and make an extension for the use case in which the generic is a Dictionary.
E.G:
public final class AtomicCollection<WrappedValue> {
}
I want to be able to implement all the methods a Dictionary/Array/Set has, for example func removeAll().
I tried to do that with an extension so:
extension AtomicCollection where WrappedValue == Dictionary {
}
The problem is, I get the following error:
Reference to generic type 'Dictionary' requires arguments in <...>
This will result in the fact that I need to mention the type of which the Key and the Value are fora Dictionary, Element is for an Array etc..
I want to be able to create a generic constraint for ALL Dictionaries, Arrays and Sets.
Any idea?
答案1
得分: 1
extension AtomicCollection where WrappedValue: Collection {}
如果你需要能够调用 removeAll()，那么协议是 RangeReplaceableCollection（这也意味着符合 Collection 协议）：
extension AtomicCollection where WrappedValue: RangeReplaceableCollection {}
你只需要选择（或创建）一个具有你所需方法的协议来应用于这组算法。这正是协议的整个目的：定义一组算法可以操作的方法。
与类似集合的协议相关的协议有相当多。你可以在 Sequence and Collection Protocols 中找到它们的概述。
英文:
The key thing is you're not asking for Dictionary. Your title captures your intent: all collections. So that's what you want:
extension AtomicCollection where WrappedValue: Collection {}
If you need to be able to call removeAll(), the protocol is RangeReplaceableCollection (which also implies Collection):
extension AtomicCollection where WrappedValue: RangeReplaceableCollection {}
You just need to pick (or create) a protocol that has the methods you need for this group of algorithms. That's the whole point of protocols: to define a set of methods that algorithms can operate on.
There are quite a few protocols related to collection-like things. You can find an overview of them in Sequence and Collection Protocols.
答案2
得分: 1
目前您可以通过为扩展中的每个函数指定通用条件来实现此目的，但不能针对整个扩展本身实现此目的：
extension AtomicCollection {
func removeAll<T1, T2>() where WrappedValue == Dictionary<T1, T2> {
}
}
英文:
Currently you can do this by specifying generic conditions for each function in the extension, but not for the whole extension itself:
extension AtomicCollection {
func removeAll<T1, T2>() where WrappedValue == Dictionary<T1, T2> {
}
}
答案3
得分: -1
这次讨论导致我创建了自己的协议，以暴露特定功能，就像@rob-napier所提供的一样。
这导致了一个简单而相当天真的解决方案，基于GCD，在Swift中适用于所有类型，包括集合。
你可以在这里查看！
https://gitlab.com/yanivhasbanidev/atomics
感谢大家对以上的帮助！
英文:
This discussion resulted in me creating my own protocols to expose specific functionalities, as offered by @rob-napier.
This resulted in a simple and quite naive solution, based on GCD, for Atomicity in Swift for every type, including collection.
You can check it out here!
https://gitlab.com/yanivhasbanidev/atomics
Thanks everyone for assisting with the above!
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
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