How to use an array of functions in Swift

user_11114752 0
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I have read all the posts I can find here about arrays of functions - great you can do it. I figured. But none of the posts show practically how to use them (at least not what I'm trying to do). Here's what I want - they can all take the same args, but that's not a requirement.

This article is close, and will allow me to loop through to execute each function (which meets the first goal).
https://stackoverflow.com/a/24447484/11114752

But... what if I want to execute a single function by reference? In other words, how to call just the referenced Arity2 function - for example:

// None of these work (with or without the parameter labels)
funcs.Arity2(n: 2, S: "Fred)    // value of type [MyFuncs] has no member .Arity2
funcs[Arity2](n: 2, S: "Fred")  // no exact matches to call in subscript
funcs[.Arity2](n: 2, S: "Fred") // Cannot call value of non-function type...

let fn = funcs.first(where: { a whole ton of permutations here to try to match Arity2 }) -- a whole lotta frustrating nope...

Help, please! Nothing I've tried works. The pre-compiler just goes in circles making suggestions that don't pan out and it will not compile.

EDIT: The reason for the array in the first place is that I'm going to have a quite a few functions, and I don't know what they all are in advance. Essentially, I want a plugin type of architecture. Where I can add to the list of functions (ideally within an extension of the class, but that's another problem..) and not change the processing loop that executes each function in order.

swift function arrays
2 Answers

I assume you need something like

    _ = funcs.first {
        if case let MyFuncs.Arity2(f) = $0 {
            f(2, "Fred")
            return true
        }
        return false
    }
user_122990300

It can be achieved in a much simpler way if you know the position of the function in the array.

Assuming you have:

func someFunc(n: Int, s: String) { 
    print("call \(n) \(s)")
}

var funcs = [MyFuncs.Arity2(someFunc)]

you can do:

if case .Arity2(let f) = funcs.first {
    f(2, "Fred")
}

By replacing funcs.first with funcs[i] you can access the i-th index (first make sure it does exist).

user_86977930
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