Oops! that is buggy. I should check syntax before posting…
Here is the corrected version:
public struct AnyKey : Hashable {
public let hashValue: Int
public let key: Any
public let equals: (Any, AnyKey) -> Bool
init<T: Hashable>(_ key: T) {
self.hashValue = key.hashValue
self.key = key
self.equals = { $0 as! T == $1.key }
}
}
public func == (lhs: AnyKey, rhs: AnyKey) -> Bool { return lhs.equals(lhs,rhs) }
> On Mar 25, 2016, at 5:59 PM, Hooman Mehr via swift-users
> <[email protected]> wrote:
>
> You can also get a heterogenous dictionary, but it needs a type erasing
> helper box. With the following declarations:
>
> public func ==<T: Equatable>(lhs: T, rhs: Any) -> Bool {
>
> if let rhs = rhs as? T { return lhs == rhs } else { return false }
> }
>
> public struct AnyKey : Hashable {
>
> public let hashValue: Int
> public let key: Any
> public let equals: (AnyKey) -> Bool
>
> init<T: Hashable>(_ key: T) {
>
> self.hashValue = key.hashValue
> self.key = key
> self.equals = { self.key as! T == $0.key }
> }
> }
>
> public func == (lhs: AnyKey, rhs: AnyKey) -> Bool { lhs.equals(rhs) }
>
> You can now create a heterogenous [AnyKey: Any] dictionary. Note that
> `AnyKey` is not very memory efficient.
>
>> On Mar 25, 2016, at 5:27 PM, Hooman Mehr <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>>
>>> On Mar 25, 2016, at 2:51 PM, Jason Sadler via swift-users
>>> <[email protected] <mailto:[email protected]>> wrote:
>>>
>>> (My particular use case can be seen here:
>>> https://gist.github.com/sadlerjw/2cc16b4375b02fe7f400
>>> <https://gist.github.com/sadlerjw/2cc16b4375b02fe7f400> … and the best
>>> information I’ve been able to find on this so far is here:
>>> http://stackoverflow.com/questions/33112559/protocol-doesnt-conform-to-itself/33524927#33524927
>>>
>>> <http://stackoverflow.com/questions/33112559/protocol-doesnt-conform-to-itself/33524927#33524927>)
>>
>> Here is the best you can do for your particular use case:
>>
>> protocol AnyEquatable { func equals(other: Any) -> Bool }
>>
>> func ==<T: Equatable>(lhs: T, rhs: Any) -> Bool {
>>
>> if let rhs = rhs as? T { return lhs == rhs } else { return false }
>> }
>>
>> extension Bool: AnyEquatable { func equals(other: Any) -> Bool { return
>> self == other } }
>>
>> extension Int: AnyEquatable { func equals(other: Any) -> Bool { return
>> self == other } }
>>
>> extension Double: AnyEquatable { func equals(other: Any) -> Bool { return
>> self == other } }
>>
>> extension String: AnyEquatable { func equals(other: Any) -> Bool { return
>> self == other } }
>>
>> extension Array {
>>
>> func indexOfAny(element : AnyEquatable) -> Index? { return indexOf {
>> element.equals($0) } }
>> }
>>
>> var array: [Any] = [false, 1, 2.0, "three"]
>>
>> array.indexOfAny(2.0)
>>
>
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