CODEWITHSUNDEEP
swiftoperator-overloadinginfix-notation
David
David

Reputation: 7456

Creating an infix operator with a parameter

Currently, I'm trying to streamline background thread to main thread executions in my application.

The way I'm doing that is this:

import Foundation

infix operator ~> {}

private let queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)

func ~> (backgroundClosure: () -> (), mainClosure: () -> ()) {
    dispatch_async(queue) {
        backgroundClosure()
        dispatch_async(dispatch_get_main_queue(), mainClosure)
    }
}

which would let me do something like:

{ println("executed in background thread") } ~> { println("executed in main thread") }

Now... I wanted to extend this functionality to potentially be able to dispatch_after to the main thread, so maybe I want it to be called 0.25 seconds later or something.

Is there a way to achieve this by passing in a parameter somehow?

Ideally, I'd be able to implement something like backgroundClosure ~>(0.25) mainClosure, but I doubt that is possible

Upvotes: 1

Views: 145

Answers (2)

t4nhpt
t4nhpt

Reputation: 5302

Just a suggestion:

infix operator ~> {}

private let queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)

func ~> (backgroundClosure: () -> (), secondParam: (delayTime:Double, mainClosure: () -> () )) {
    // you can use the `delayTime` here
    dispatch_async(queue) {
        backgroundClosure()
        dispatch_async(dispatch_get_main_queue(), secondParam.mainClosure)
    }
}

How to use:

{ print("executed in background thread") } ~> (0.25, { print("executed in main thread") })

Upvotes: 2

Vandilson Lima
Vandilson Lima

Reputation: 54

try this:

private let queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)

infix operator ~>{ associativity left precedence 140}

func ~> (backgroundClosure: ()->() , mainClosure: ()->()) {
dispatch_async(queue) { () -> Void in
    backgroundClosure()
    dispatch_async(dispatch_get_main_queue(), { () -> Void in
        mainClosure()
    })
}}

Upvotes: 0

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