closures

问题 Given following groovy function: def foo(List<String> params, Closure c) {...} The method call would be: foo(['a', 'b', 'c']) { print "bar" } But I would like to get rid of brackets (List) in the function call. something like: foo('a', 'b') { print "bar" } I cannot change the list parameter to varargs because varargs can be only the last parameter in function (here the closure is the last one). Any suggestion? 回答1: Seeing that it's impossible to achieve exactly what you want (it's written in

问题 Quoted from the Adobe ColdFusion 10: Using closures documentation: function helloTranslator(String helloWord) { return function(String name) { return "#helloWord#, #name#"; }; } How to scope helloWord and name properly on the return line? Are they both in Arguments scope? If that's the case, they must be unique? The Closures and functions section also mentions there are 4 more scopes on top of the already long scope search: In closure, following is the order of search for an unscoped variable

问题 I noticed in JQuery that the following code structure is used (function(){var l=this,g,y=l.jQuery,p=l.$,...})() Which seems to create a function, and call it. What is the benefit of taking this approach versus having the contents of the function inline? 回答1: It creates a closure to prevent conflicts with other parts of code. See this: http://docs.jquery.com/Plugins/Authoring Particularly handy if you have some other library that uses the $() method and you have to retain the ability to use

问题 I want to define like this: public var reloadFRCsNeedToPerformWhenFail = [()->()]() but I get an error 回答1: Like this: public var reloadFRCsNeedToPerformWhenFail : [()->()] = [] If you use a type alias to make ()->() a type, you can do it your way: public typealias VoidVoid = ()->() public var reloadFRCsNeedToPerformWhenFail = [VoidVoid]() Or, forego the [] shortcut notation and use the full generic: public var reloadFRCsNeedToPerformWhenFail = Array<()->()>() 来源： https://stackoverflow.com

问题 In my project, I have both Objective-C and Swift code. I have some objects that have properties containing blocks to clean up some UITableView configuration. Using it works in Objective-C, but crashes when using Swift. I have reduced the problem to be as minimal as possible, while still being reproducible. // in Objective-C @interface MyClass : NSObject @property (copy, nonatomic) NSString* (^block)(); - (NSString *)callTheBlock; @end @implementation MyClass - (NSString *)callTheBlock { if

问题 This function returns two different values depending on the way its called. I understand that Closures close over variables, not over values and I expected the values returned from the second call to be the same regardless of how the function is called static Func<int, int,int> Sum() { var test = 1; return (op1, op2) => { test = test + 1; return (op1 + op2) + test; }; } Here is the call: var mFunc = Sum(); Console.WriteLine("Calling Sum(1,1) with Invoke() " + Sum().Invoke(1, 1)); Console

问题 I have a Javascript code as below, http://jsfiddle.net/ramchiranjeevi/63uML/ var foo = 1; function bar() { foo = 10; return; function foo() {} } bar(); console.log(foo); // returns 1 When the code executed, the bar() function is called and the global variable is overwritten with value 10, then the log should be printed as 10 instead it is printed as value 1. 回答1: Because of a concept called "hoisting", function declarations are "moved" to the top of the scope. When that happens, a new foo

问题 Consider this code: PS> $timer = New-Object Timers.Timer PS> $timer.Interval = 1000 PS> $i = 1; PS> Register-ObjectEvent $timer Elapsed -Action { write-host 'i: ' $i }.GetNewClosure() PS> $timer.Enabled = 1 i: 1 i: 1 i: 1 ... # wait a couple of seconds and change $i PS> $i = 2 i: 2 i: 2 i: 2 I assumed that when I create new closure ( { write-host 'i: ' $i }.GetNewClosure() ) value of $i will be tied to this closure. But not in this case. Afer I change the value, write-host takes the new value

问题 I am attempting to design a basic compiler to pseudo-assembly code. However, I cannot figure out how to implement closures. It seems I would need to associate specific register values with each "subroutine". I've considered use of stacks, but once again it seems insufficient. It seems like nothing short of an associative array would work, but how could that, or something similar, be done in assembly? The example I have chosen to attempt to represent is the following, communicated as

问题 I'm very new to javascript, recently while understanding closures I came across one question asked by Interviewer:- function initButtons() { var body = document.body, button, i; for (i = 0; i < 5; i++) { button = document.createElement("button"); button.innerHTML = "Button " + i; button.addEventListener("click", function (e) { alert(i); }, false); body.appendChild(button); } } initButtons(); What will be output of this code? For which I replied - "Number corresponding to button.. 1, 2 etc."