closures

问题 This question already has answers here : Javascript function scoping and hoisting (16 answers) Closed 2 years ago . I just can't understand why the the a1 = function ? and where is my value 1 that was passed to the fn() , whether it was overrwrited by var a ? the problem look like caused by the same names( var & function) ! function fn(a) { console.log("a1 = " + a); var a = 2; function a() { } console.log("a2 = " + a); } fn(1); // a1 = function a() { } // a2 = 2 function fnx(ax) { console.log

问题 I am new to swift language and I have problem that I can't solve. After running my app i get output of empty String: nil So, my question is how to add value to variable inside closure ? Because when I add line inside closure print(self.latLong) I get output of coordinates, but I need that value inside of variable because I need to manipulate with that variable later in my code and I don't want to write all functionality inside that closure This is my code: import UIKit import CoreLocation

问题 Hi I'm trying to recreate what http://austintexas.wayblazer.com/locations/austin-tx is doing for its search textbox - displaying typed character and rotating between several phrases. My initial logic is to read the phrases from an array like so: [abc,123,XYZ] and then to use a split and forEach to separate the string into characters and create a typing effect using setTimeout . However, when I attempt this logic, I seem to have trouble getting the desired effect. I've been reading through a

问题 This question extends my previous one Groovy equivalent for Scala implicit parameters Not sure if this is the right way to develop from a previous topic, but anyway.. I am looking for a way to express in groovy something like this: // scala object A { def doSomethingWith(implicit i:Int) = println ("Got "+i) } implicit var x = 5 A.doSomethingWith(6) // Got 6 A.doSomethingWith // Got 5 x = 0 A.doSomethingWith // Got 0 In general, I would like to execute a piece of logic, and have variables in

问题 There are some other questions on here that are similar but sufficiently different that I need to pose this as a fresh question: I have created an empty class, lets call it Test. It doesn't have any properties or methods. I then iterate through a map of key/value pairs, dynamically creating properties named for the key and containing the value... like so: def langMap = [:] langMap.put("Zero",0) langMap.put("One",1) langMap.put("Two",2) langMap.put("Three",3) langMap.put("Four",4) langMap.put(

问题 This is purely a curiosity question for me: So for fun, one can easily redefine cons, car, and cdr like so: (define cons+ (lambda (a b) (lambda (f) (f a b) ))) (define car+ (lambda (f) (f (lambda (a b) a)))) (define cdr+ (lambda (f) (f (lambda (a b) b)))) This creates the basic functionality of a list using closures. In this context, what would be the best way to define an empty list? 回答1: There's no particular special value that you need as the empty list; you just need something and then to

问题 I have watched the talk of Robert C Martin "Functional Programming; What? Why? When?" https://www.youtube.com/watch?v=7Zlp9rKHGD4 The main message of this talk is that a state is unacceptable in functional programming. Martin goes even further, claims that assigments are 'evil'. So... keeping in mind this talk my question is, where is a place for closure in functional programming? When there is no state or no variable in a functional code, what would be a main reason to create and use such

问题 Note : this question is a follow up of the recently asked question JavaScript: automatic getters and setters in closures without eval? . The gist of that question was as follows: "How can one automatically provide getters and setters for scoped variables in a closure - without the use of the eval statement". There the poster, provided code demonstrating how to do so with eval and the user gave the following answer which does not require eval : function myClosure() { var instance = {}; var

问题 This question already has answers here : Nil cannot be assigned to type ()->()? (3 answers) Swift 3 optional escaping closure parameter (5 answers) Closed 2 years ago . Thanks to the marvels of Swift, we can have: func someFunction(someParameter: someType, someOtherParameter: someOtherType) We call it like so: someFunction(x, y) We also have this: func someFunction(someParameter: someType, someOtherParameter: someOtherType?) We may call this like so: someFunc(x, y) OR someFunc(x, nil) However

问题 Problem & Reason One of my team mate ended up in messy situtaion implementing function hooking in javascript. this is the actual code function ActualMethod(){ this.doSomething = function() { this.testMethod(); }; this.testMethod = function(){ alert("testMethod"); }; } function ClosureTest(){ var objActual= new ActualMethod(); var closeHandler = objActual.doSomething; closeHandler(); closeHandler.apply(objActual,arguments); //the fix i have added this.ActualTest = function() { alert(