The following methods are defined as static on the class ExSwift.

• Methods
• after
• once
• partial
• bind
• cached

#Methods

###after

• after <P, T> (n: Int, call: (P...) -> T) -> ((P...) -> T?)
• after <T> (n: Int, call: Void -> T) -> (Void -> T?)

Creates a wrapper that, executes function only after being called n times.

let f = ExSwift.after(2, { println("Ciao") })
f()
// → 
f()
// → 
f()
// → Ciao
f()
// → Ciao

###once

• once <P, T> (call: (P...) -> T) -> ((P...) -> T?)
• once <T> (call: Void -> T) -> (Void -> T?)

Creates a wrapper that, when called for the first time (only) invokes function.

let greet = ExSwift.once { (names: String...) -> () in println("Hello " + names[0]) }

greet("World")
// → Hello World

greet("People")
// → 

###partial

• partial <P, T> (function: (P...) -> T, _ parameters: P...) -> ((P...) -> T)

Creates a wrapper that, when called, invokes function with any additional partial arguments prepended to those provided to the new function.

let add = {
    (params: Int...) -> Int in
    return params.reduce(0, { return $0 + $1 })
}

let add5 = ExSwift.partial(add, 5)

add5(10)
// → 15

add5(1, 2)
// → 8

###bind

• bind <P, T> (function: (P...) -> T, _ parameters: P...) -> (Void -> T)

Creates a wrapper (without any parameter) that, when called, invokes function automatically passing parameters as arguments.

let concat = {
    (params: String...) -> String in
    return params.implode(" ")!
}

let helloWorld = ExSwift.bind(concat, "Hello", "World")

helloWorld()
// → Hello World

###cached

• cached <P, R> (function: (P...) -> R, hash: ((P...) -> P)) -> ((P...) -> R)
• cached <P, R> (function: (P...) -> R) -> ((P...) -> R)

Creates a wrapper for function that caches the result of function's invocations. hash, if specified, is the parameters based hashing function that computes the key used to store each result in the cache.

// Slow Fibonacci
func fib(params: Int...) -> Int {
    let n = params[0]
    
    if n <= 1 {
        return n
    }
    return fib(n - 1) + fib(n - 2)
}

let fibonacci = Ex.cached(fib)

// This one is computed (fib is called 465 times)
fibonacci(12)

// The results is taken from the cache (fib is not called)
fibonacci(12)