anonymous-function

Is there a way to pass anonymous function as a custom callback function in Javascript? I have this code: function notifyme(msg){ console.log(msg) } notifyme("msg", function(){ //do some custom redirect logic }); I am trying the above code and it's executing notifyme function, but not going further with redirect code. I know I can pass a function name as a callback, but I don't have a specific function that I can pass. This is why they invented the anonymous function I guess. It'd be really nice if there was a way to do that. Your code pattern should be like function notifyme(msg,callback){

Possible Duplicate: Calling closure assigned to object property directly Why this is not possible in PHP? I want to be able to create a function on the fly for a particular object. $a = 'a'; $tokenMapper->tokenJoinHistories = function($a) { echo $a; }; $tokenMapper->tokenJoinHistories($a); With $obj->foo() you call methods, but you want to call a property as a function/method. This just confuses the parser, because he didn't find a method with the name foo() , but he cannot expect any property to be something callable. call_user_func($tokenMapper->tokenJoinHistories, $a); Or you extend your

I have a function, and would like to obtain its parameter types and return type for use in Scala macros. scala> val fn = (a: String, b: Double) => 123 fn: (String, Double) => Int = <function2> scala> fn.getClass res1: Class[_ <: (String, Double) => Int] = class $anonfun$1 In the above example, the parameter types and return type already get printed at both lines, but I don't know how to access them. Even with toString I'd be stuck with the <function2> and class $anonfun$1 parts right of the = sign -- otherwise a bit of ugly string parsing might have done. I found that the MethodSymbolApi

I am trying to learn JavaScript but I've come across a hurdle. If the answer is obvious and reachable through a simple search I apologize in advance. I am a novice to programming and JavaScript, and unsure what line of inquiry to follow. In the following code, the function takes values from a HTML form, does some processing and sends them back. I've tested the input and output process and it's working correctly. function foo() { var x = parseInt(document.formdata.fieldone.value); var y = parseFloat(document.formdata.fieldtwo.value); if (isNaN(y)) { var z = x; } else { var z = function(x, y) {

My original (working) code looks like: jQuery().ready(function ($) { $('[id="errorMessages"]').ajaxStart(function () { $(this).html(""); }); $('[id="errorMessages"]').ajaxError(function (e, jqxhr, settings, exception) { //... }); }); When I am trying to replace the anonymous functions into a named function calls like: (I am doing a POC for some requirement, which expects such implementation.) function fs() { $(this).html(""); } function fe(e, jqxhr, settings, exception) { //... } jQuery().ready(function ($) { $('[id="errorMessages"]').ajaxStart(fs()); $('[id="errorMessages"]').ajaxError(fe(e,

I have found few kinds of anonymous function syntax in scala: val m5_1 = { (n: Int) => n * 5 } val m5_2 = (n: Int) => { n * 5 } : Int val m5_3: Int => Int = n => { n * 5 } Is that all types or some more syntax kinds present? Are they all equivalent? Which one is more/less preferred? How can I specify the return type in m5_1 ? I'll try to add to @pamu's answer: Which one is more/less preferred? I'd say the second variant is a bit uncommon. When the type inference is easily visible, you can go for the first, otherwise being explicit as in the third case is good. You don't need braces there, so a

I was reading In JavaScript, what is the advantage of !function(){}() over (function () {})()? then it hit me, why use : (function(){})() or !function(){}() instead of just function(){}() ? Is there any specific reason? It depends on where you write this. function(){}() by itself will generate a syntax error as it is evaluated as function declaration and those need names. By using parenthesis or the not operator, you enforce it to be interpreted as function expression , which don't need names. In case where it would be treated as expression anyway, you can omit the parenthesis or the operator.