closures

I'm trying to group some exisiting top-level functions inside a closure (to avoid polluting the global namespace) but I'm not quite getting it to work. First, all the JS works outside my anonymous function, but once I put it in the anonymous function I get an error of "crossfade is not defined". Does anyone see anything completely obvious that I am missing? I'm not quite getting why the the setInterval/crossfade works outside the anonymous function but not inside. Anything inside start() should be able to see vars/functions outside start() and it should all be protected in the closure created

I am trying to check if UserNotifications are enabled and if not I want to throw an alert. So I have a function checkAvailability which checks multiple things, including the UserNotification authorization status. func checkAvailabilty() -> Bool { // // other checking // var isNotificationsEnabled = false UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound], completionHandler: { (granted, error) in if granted { isNotificationsEnabled = true } else { isNotificationsEnabled = false } }) } if isNotificationsEnabled { return true } else { // Throw alert: Remind user to

We have been debating how best to handle objects in our JS app, studying Stoyan Stefanov's book, reading endless SO posts on 'new', 'this', 'prototype', closures etc. (The fact that there are so many, and they have so many competing theories, suggests there is no completely obvious answer). So let's assume the we don't care about private data . We are content to trust users and developers not to mess around in objects outside the ways we define. Given this , what (other than it seeming to defy decades of OO style and history) would be wrong with this technique? // namespace to isolate all

I have this really basic code in a MVC controller action. It maps an Operation model class to a very basic OperationVM view-model class . public class OperationVM: Operation { public CategoryVM CategoryVM { get; set; } } I need to load the complete list of categories in order to create a CategoryVM instance. Here's how I (try to) create a List<OperationVM> to show in the view. public class OperationsController : Controller { private SomeContext context = new SomeContext (); public ViewResult Index() { var ops = context.Operations.Include("blah...").ToList(); Mapper.CreateMap<Operation,

I'm reading 'CreateSpace An Introduction to Programming in Go 2012' and on page 86 I found this evil magic func makeEvenGenerator() func() uint { i := uint(0) return func() (ret uint) { ret = i i += 2 return } } // here's how it's called nextEven := makeEvenGenerator() fmt.Println(nextEven()) fmt.Println(nextEven()) fmt.Println(nextEven()) 1) Why is i not resetting ? 2) is nextEven() returning and uint or is Println so smart that it can work with everything ? For the sake of clarity, I'll assign names to both functions: func makeEvenGenerator() func() uint { // call this "the factory" i :=

So recently I understand the concept of function closure. def outer(): somevar = [] assert "somevar" in locals() and not "somevar" in globals() def inner(): assert "somevar" in locals() and not "somevar" in globals() somevar.append(5) return somevar return inner function = outer() somevar_returned = function() assert id(somevar_returned) == id(function.func_closure[0].cell_contents) As much as I understand, the objective of function closure is to keep an active reference to the object, in order to avoid garbage collection of this object. This is why the following works fine : del outer somevar

I'm trying to use an Objective-C library which expects a NSDictionary as its return type. Within the NSDictionary , I can return values of any type, including blocks. I cannot figure out if there is a way to write an analogous swift method that returns a Dictionary with a closure or a string as a possible value type. I can't use AnyObject as the value type for the dictionary so this doesn't work: Dictionary<String,AnyObject> = ["Key":{(value:AnyObject) -> String in return value.description] I get a Does not conform to protocol error from the compiler regarding the closure and AnyObject . Is