closures

问题 I am unable to access objects declared and initialized outside the call() method of JavaRDD. In the below code snippet, call() method makes a fetch call to C* but since javaSparkContext is defined outside the call method scope so compiler give a compilation error. stringRdd.foreach(new VoidFunction<String>() { @Override public void call(String str) throws Exception { JavaRDD<String> vals = javaFunctions(javaSparkContext).cassandraTable("schema", "table", String.class) .select("val"); } }); In

问题 I have the following code to create an observable property for data binding. It's in the works so I'm not sure what the final implementation is going to be and I'm still pretty new to Swift. class Observable<T> { typealias Observer = T -> Void var value: T { didSet { for observer in self.observers { observer?(self.value) } } } var observers: [Observer?] = [] init(_ val: T) { self.value = val } } I would like to keep weak references to the Observer closures. I don't want to rely on the client

问题 Some time ago, Borland have introduced in their BCB evironment an extension to C++ language. This extension is a __closure keyword. The question is, if it is possible to implement such functionality in plain C++ or C++11? If you are not familiar with __closure keyword, below code provides explanation in comments. Thanks in advance! Toreno #include <stdio.h> // __closure keyword is used here ! typedef void (__closure * MemberCallback)(int x, int y, int z); class A { private: MemberCallback

问题 I am having the code below and javascript's closure together with anonymous functions are giving me a headache. for (var i = 0, len = sites.length ; i < len ; i++) { $("#thumb"+i).click(function() { $("#shader").show(); $("#thumbInfo"+i).show(); alert("#thumbInfo"+i); }); $("#thumbInfo"+i+" .xbutton").click(function() { $("#shader").hide(); $("#thumbInfo"+i).hide(); }); } Due to closure, i is always 5 (the sites array has 5 elements), so all the click handlers refer to the same id. Any

问题 I have an IIFE that I am trying to make into a bookmarklet. I would like to have the modal the bookmarklet will pop up have some buttons that will call a function. However, when I have a structure like this: (function(){ var __myFn = function(str){ //also have tried function __myFn(){..} alert(str); } //some AJAX that builds HTML with the `result`s document.getElementById("resultDiv").innerHTML = "<span onclick='__myFn(" + result.someData+ ")'>test</span> }()); I get Uncaught ReferenceError:

问题 I am trying to write a function that can be used to inspect the properties of an object. For example, for the given object: var obj = { s : 'a', n : 1, d : new Date(), f : function(){}, a : [], o : { a : { b: 'b' } } }; I could use my inspector function to access to properties: var ins = inspector(obj); ins('s') // -> a ins('n') // -> 1 ins('d') // -> 2018-12-06T11:51:26.244Z ins('f') // -> [Function] ins('a') // -> [] ins('o') // -> { a: { b: 'b' } } ins('o.a') // -> { b: 'b' } ins('o.a.b')

问题 I get a weird error in my iOS swift app. The compiler complains at the first row of: let task = session.dataTaskWithRequest(request) { data, response, error in self.oauthManager.customOAuth2Manager.parseData(data, response: response, error: error, body:request, callback: { (jsonArray, error) -> Void in }) } The compiler error is: Cannot invoke 'dataTaskWithRequest' with an argument list of type '(NSURLRequest, (_, _, _) -> _)' However, it's not on that row the error seems to be located. If I

问题 This question relates to another question: passing a closure in a plugin extension in gradle The solution was to call the closure with .call() . Why does this work instead of directly calling the closure? 来源： https://stackoverflow.com/questions/56467564/why-does-directly-calling-groovy-closure-not-work-but-using-call-does

问题 Most of us know that JavaScript has no sense of "private" properties, but that behavior can be emulated through the use of closures: var Car = function () { var name = 'Tesla'; var wheelCount = 4; this.getName = function () { return name; }; this.getWheelCount = function () { return wheelCount; }; this.setName = function (newName) { name = newName; }; this.setWheelCount = function (newCount) { wheelCount = newCount; }; }; var myCar = new Car(); console.log(myCar.name); // undefined That all

问题 I use the cassandra of the c/c++ driver to query, and then return the data. Therefore, both cass (LinkedList) and cass_it (Vec) can show the result of the query. However, I want to display the results to the web using the json format, so I chose to reassemble the data using vec. However, there is a problem： error[E0434]: can't capture dynamic environment in a fn item --> src/main.rs:306:42 | 306 | let out = serde_json::to_string(&cass_it).unwrap(); | ^^^^^^^ | = help: use the `|| { ... }`