PHP function use(*) all

Question

I often pass local variables to functions declared in variables like:

public function getTotal($tax)
{
    $total = 0.00;

    $callback =
        /* This line here: */
        function ($quantity, $product) use ($tax, &$total)
        {
            $pricePerItem = constant(__CLASS__ . "::PRICE_" .
                strtoupper($product));
            $total += ($pricePerItem * $quantity) * ($tax + 1.0);
        };

    array_walk($this->products, $callback);
    return round($total, 2);
}

Is it possible to pass every local variable that is declared in the same scope as declared function without listing them all like use($a,$b,$c ...)?

So if I would like like use(*) everything that was accessable in parent scope will be passed to declared function scope?

You use improper approach. Since you use OOP you can define needed callback as a method of the same class and then you can pass all needed data through class properties. — hindmost
– hindmost, Commented Aug 20, 2014 at 14:07
@hindmost I was about to suggest the same, but I realized for a local use case, such as walking an array. The fact the method would need to be public to pass as a callback would prove to be clutter. — Flosculus
– Flosculus, Commented Aug 20, 2014 at 14:11
@Flosculus That's not right. The fact that the method only must be public if it used/called outside of its class (object). Otherwise it might have any level of visibility, i.e. it can be protected or even private. — hindmost
– hindmost, Commented Aug 20, 2014 at 14:43

Clément Malet · Accepted Answer · 2014-08-20 14:03:50Z

2

get_defined_vars could do the job for you

$a = 1;

function test ($c) {
  $b = 2;
  var_dump(get_defined_vars()); // var_dump for the generic example, adapt as you need for use
}

test(3);

// array(2) { ["c"]=> int(3) ["b"]=> int(2) }

You will have to use these vars from an array though.

answered Aug 20, 2014 at 14:03

Clément Malet

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2 Comments

Justinas Over a year ago

But in another function, there will be no local variables from previous function

Clément Malet Over a year ago

@Justinas OP is looking for local variables declared in the same scope, not for all the variables

Flosculus · Accepted Answer · 2014-09-03 12:58:41Z

1

Closures should be very limited in what they do. 4-5 lines tops really.

In my mind, it is far better to define the variables being made available to it as closures are essentially unstructured.

I usually inline them like this though:

array_walk($this->products, function ($quantity, $product) use ($tax, &$total) {

});

The new operation of the use keyword might be a bit cumbersome, but it is better than global. This is a much more manageable can of worms.

edited Sep 3, 2014 at 12:58

answered Aug 20, 2014 at 14:16

Flosculus

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Comments

Justinas · Accepted Answer · 2014-08-20 14:04:10Z

0

No, you have to list all variables, that you pass to function. You can add them to some array and pass as single argument. But you can use func_get_args to get all variables, passed to function and not list all of them in function header.

answered Aug 20, 2014 at 14:04

Justinas

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Comments

Michael · Accepted Answer · 2024-10-10 12:43:08Z

0

You can use get_defined_vars and extract.

$a = 1;
$b = 2;

$vars = get_defined_vars();

(function () use ($vars)
{
    extract($vars);
    
    echo $a; // Outputs 1
    echo $b; // Outputs 2
})();

answered Oct 10, 2024 at 12:43

Michael

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