A closure iku anonimus function (fungsi tanpa jeneng, disimpen ing variabel). A callable iku apa wae sing PHP iso dijalani minangka fungsi — closure, fungsi jeneng, method, utawa objek invokable. Dheweke mengkono functional-style programming, callback, lan higher-order function.
= {
* ;
};
();
= * ;
();
A closure iku anonimus function sing iso disimpen lan diliwatake. The arrow function (fn) iku bentuk singkat sing otomatis ngabdul outer variable.
$factor = 10;
// traditional closure — must explicitly import variables with `use`
$multiply = function (int $x) use ($factor): int {
return $x * $factor; // $factor captured by value
};
// arrow function — captures outer variables AUTOMATICALLY (no `use` needed)
$multiply = fn(int $x): int => $x * $factor;
Bedaning utama: traditional closure kudu explicit use clause kanggo ngabdul outer variable, dene arrow function ngabdul automatic — convenience gedhé banget kanggo short callback.
// these are all callables, usable as callbacks:
'strlen' // a string naming a function
[$object, 'methodName'] // [object, method] array
['ClassName', 'staticMethod'] // [class, static method]
fn($x) => $x * 2 // a closure/arrow function
$invokableObject // an object with __invoke()
// used with higher-order functions:
array_map(fn($x) => $x * 2, [1, 2, 3]); // [2, 4, 6]
array_filter($users, fn($u) => $u->isActive()); // filter
usort($items, fn($a, $b) => $a->price <=> $b->price); // custom sort
callable iku type hint kanggo parameter sing nerima callable apa wae — mengkono higher-order function (fungsi sing nerima fungsi), basis saka array_map/array_filter/usort lan callback-based API.
Closure lan callable iku feature PHP penting sing mengkono functional-style programming, callback, lan higher-order function — pola sing dienggo terus-terusan ing PHP modern.
Ngerti closure (anonimus function disimpen ing variabel) lan khususne arrow function (fn, sing otomatis ngabdul outer variable, ora kaya traditional closure sing kudu explicit use clause) iku pengetahuan saben hari, sebab closure iku cara alami nulis short inline function sing diliwatake menyang array function (array_map/array_filter/array_reduce), custom sort (usort), event handler, lan callback-based API.
Ngerti apa sing dadi callable (named function, method, static method, closure, invokable object) lan carane higher-order function nerima dheweke iku penting kanggo nulis clean, functional-style PHP lan nggunakake akeh framework lan standard-library API sing nerima callback (route handler, collection method, middleware).
Closure lan callable iku fundamental kanggo expressive modern PHP — dheweke nggawe data transformation, filtering, sorting, lan callback pattern singkat lan readable — mula master dheweke, khususne convenient arrow-function syntax lan capture-by-use-vs-auto distinction, iku practical, frequently-applied knowledge kanggo productive PHP development.