PHP closure return multiple functions

Question

I'm trying to achieve almost similar things/properties of closure in PHP which is available in JS.

For example

function createGreeter($who) {
    return function(){
        function hello() use ($who) {
            echo "Hi $who";
        }

        function bye() use($who){
            echo "Bye $who";
        }
    };
}

I know my syntax is incorrect, this what I'm trying to achieve.

What I've done so far is.

function createGreeter() {
    $hi = "hi how are you.";
    $bye = "bye wish you luck.";
    return function($operation) use ($hi, $bye){
        if ($operation == "a") return $hi;
        elseif ($operation == "b") return $bye;
    };
}
$op = createGreeter();
echo $op("a"); #prints hi how are you.
echo $op("b"); #prints bye wish you luck.

Please look does PHP allows us to do this.

`return ['hello' => function () use ($who) { ... }, ...]`…? — deceze, Apr 28 '20 at 09:36
@B001ᛦ just for curiosity, I already knew that can be easily done by OOPS but this time, I just want to go with procedure-oriented never mind. — Rupesh Arora, Apr 28 '20 at 09:49

score 4 · Accepted Answer · answered Apr 28 '20 at 09:40

4

You could return an anonymous class which is created with the $who and then has methods which output the relevant message...

function createGreeter($who) {
    return new class($who){
        private $who;
        public function __construct( $who ) {
            $this->who = $who;
        }
        function hello() {
            echo "Hi {$this->who}";
        }

        function bye(){
            echo "Bye {$this->who}";
        }
    };
} 
$op = createGreeter("me");
echo $op->hello();    // Hi me
echo $op->bye();      // Bye me

answered Apr 28 '20 at 09:40

Nigel Ren

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I knew this method, what I mean by OOPS we can easily do it. But can we do it in a procedural way too? – Rupesh Arora Apr 28 '20 at 09:51
Do you mean you want to do something like [this](https://medium.com/@frederico.de.paoli/javascript-multiple-closures-88bfa06de3f4)? – Nigel Ren Apr 28 '20 at 10:14
Look at this something like that [this](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Closures#Emulating_private_methods_with_closures) – Rupesh Arora Apr 28 '20 at 11:41

score 3 · Answer 2 · answered Apr 28 '20 at 11:51

Decided to post as a new answer as it's a completely different solution. This follow the idea of creating private methods using closures (as linked to by OP in comment to my other answer - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Closures#Emulating_private_methods_with_closures).

This also draws on deceeze's comments on the original question, but casting the array to an object to more closely reflect the reference as being an object rather than an array...

function createGreeter($who) {
    return (object)
    [ "Hello" => function() use ($who) {
        echo "Hello {$who}";
    },
    "Goodbye" => function() use ($who) {
        echo "Goodbye {$who}";
    }];
} 
$op = createGreeter("me");
($op->Hello)();
($op->Goodbye)();

The ()'s around the methods are needed as it is a closure and not an actual method.

This gives...

Hello meGoodbye me

PHP closure return multiple functions

2 Answers2