I would say that anonymous functions show their beauty when there is good library classes/functions that use them. They are not that sexy by themselves. In the world of .net there is technology called LINQ that makes huge use of then in very idiomatic manner. Now back to PHP. First example, sort: uasort($array, function($a, $b) … Read more
lambdas can only contain expressions – basically, something that can appear on the right-hand side of an assignment statement. pass is not an expression – it doesn’t evaluate to a value, and a = pass is never legal. Another way of thinking about it is, because lambdas implicitly return the result of their body, lambda: … Read more
I think the problem lies with using single line comments //. Single-line comments enclosed in /* .. */ seem to work fine. Here’s an equivalent example with something other than a comment. $(‘element’).hover( -> console.log(“first”) -> console.log(“second”) ) Or with comments using /* .. */. $(‘element’).hover( -> /* first */ -> /* second */ ) … Read more
This is based on Udi’s nice answer. I think that the difficulty of creating anonymous functions is a bit of a red herring. What you really want to do is to keep related code together, and make the code neat. So I think decorators may work for you. import re # List of pairs (regexp, … Read more
This declaration (at block scope): int (*max)(int, int) = ({ int __fn__ (int x, int y) { return x > y ? x : y; } __fn__; }); is not C but is valid GNU C. It makes use of two gcc extensions: nested functions statement expressions Both nested functions (defining a function inside a … Read more
The first two cases show function expressions, and can appear anywhere an expression like (1+1 or x*f(4)) would appear. Just like how 1+1, evaluates to 2, these expressions evaluate to a corresponding function. The third case is a function declation statement, and can appear anywhere you can have other statements (like an if or while … Read more
There’s no difference. Both are valid ways to get the JavaScript parser to treat your function as an expression instead of a declaration. Note that + and ! will also work, and are sometimes used by minifiers to save a character of size: +function() { var foo = ‘bar’; }(); !function() { var foo = … Read more
Put your cursor in the anonymous function (between the {}’s) and press F9.
You are missing some code there, but I assume its part of an object declaration like this: var obj = { queryString: function() { //some code } }; obj.queryString(); It assigns a function as a property of an object literal. It would be equivalent to this: var obj = {}; obj.queryString = function() { … … Read more
You can use the use keyword to inherit variables from the parent scope. In your example, you could do the following: $callback = function($val) use ($avg) { return $val < $avg; }; For more information, see the manual page on anonymous functions. If you’re running PHP 7.4 or later, arrow functions can be used. Arrow … Read more