Thanks for the tip about 'concurrentPerform'!
> On Jan 23, 2017, at 5:34 PM, Jon Shier <j...@jonshier.com> wrote:
>
> enumerateObjects(options:using:) exists on NSArray in Swift. And I was able
> to create your generic class just fine:
>
> class Test<T> {
> var array: [T] = []
>
> init() {
> var temp = array as NSArray
> }
> }
>
> I’m not sure what the canonical parallel array enumeration would be, but you
> can do it using concurrentPerform:
>
> let array = [“one”, “two”]
> DispatchQueue.concurrentPerform(iterations: array.count) { index in
> print(array[index])
> }
>
>
>> On Jan 23, 2017, at 8:20 PM, Doug Hill via swift-users
>> <swift-users@swift.org <mailto:swift-users@swift.org>> wrote:
>>
>> I'm trying to accomplish the equivalent functionality of -[NSArray
>> enumerateUsingObjects:…] in Swift. Doing a Googles search, I see that one
>> would need to call the equivalent method on the bridged NSArray version of
>> your Swift array:
>>
>> var myNSArray : NSArray = mySwiftArray as NSArray
>>
>> Here's the problem I'm running into; I have the following class:
>>
>> class Tester<typeA>
>> {
>> var myArray : [typeA]
>>
>> init()
>> {
>> var temp = self. myArray as NSArray
>> }
>> }
>>
>> Which produces a compiler error:
>>
>> 'cannot convert value of type '[typeA]' to type 'NSArray' in coercion'
>>
>> Ok, this makes some sense since I'm guessing NSArray requires each element
>> to to be an NSObject but this array type Array<typeA> could be a
>> non-NSObject.
>>
>> However, this makes my code harder to write since I now have to make sure
>> any array has element type NSObject to use enumerateUsingObjects. Not
>> something I can either guarantee or even desire.
>>
>> The reason I like enumerateUsingObjects is that it supports a functional
>> style of programming and is better at creating work items for each object by
>> dispatching each array item on multiple cores/processors/threads for me.
>> Writing this method myself would require figuring out to pass an object to a
>> dispatch invocation. But looking through the swift API's, I don't see any
>> GCD method for passing an object to dispatch_sync/async. I see versions of
>> these methods that takes a context parameter but then takes a C function
>> instead of a block, so not very Swift-like and potentially unsafe.
>>
>> Does this mean enumerateUsingObjects is generally not all that useful in
>> Swift? Are there better alternatives? Any ideas on how best to handle this
>> situation would be appreciated.
>>
>> Doug Hill
>> _______________________________________________
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>> swift-users@swift.org <mailto:swift-users@swift.org>
>> https://lists.swift.org/mailman/listinfo/swift-users
>
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