can swift functions and closures conform to Hashable?

问题

Suppose I want to have a Set of functions or closures. Here's how I would go about it:

typealias HandlerX = () -> ()
static var handlersX = Set<HandlerX>()

This produces the following compiler error:

Type 'HandlerX' (aka '() -> ()') does not conform to protocol 'Hashable'

Is this a dead end?

回答1:

Yes, this is a dead end. Hashable isn't really your problem; there's no way to decide whether two closures are Equal (which is a base requirement of Hashable).

来源：https://stackoverflow.com/questions/35161853/can-swift-functions-and-closures-conform-to-hashable