Online PHP editor | output for 3OKGT

@ 2019-08-11T16:59:23Z

<?php

class Collection
{
	private $items;
	private static $macros = [];

    public static function macro($name, callable $macro)
    {
        static::$macros[$name] = Closure::fromCallable($macro);
    }
    
    public static function mixin($class)
    {
        foreach (get_class_methods($class) as $method) {
            static::macro($method, $class->$method());
        }
    }

    public function __construct(array $items)
    {
    	$this->items = $items;
    }
    
    public function map(callable $callback)
    {
    	return new static(array_map($callback, $this->items));
    }

    public function all()
    {
    	return $this->items;
    }
    
    public function exampleClosure()
    {
        return function () {
            return $this->items;
        };
    }
    
    public function __call($method, $args)
    {
        return static::$macros[$method]->bindTo($this, static::class)(...$args);
    }
    
    public static function __callStatic($method, $args)
    {
        return static::$macros[$method]->bindTo(null, static::class)(...$args);
    }
}

Collection::macro("flatMap", function (callable $callback) {
	$tmp = [];
	foreach ($this->items as $item) {
		$tmp = array_merge($tmp, $callback($item));
	}

	return new static($tmp);
});

$items = new Collection(["a", "b", "c"]);
$items = $items->flatMap(function ($item) {
	return [$item, $item];
});

if ($items->all() === ["a", "a", "b", "b", "c", "c"]) {
	echo "it works";
}

// This is the thing that is deprecated and causes a warning:
// Here we're removing $this from a closure that isn't static
// All non-static closures will have a $this in PHP 8.x when defined in a method
try {
    var_dump(
        $items->exampleClosure()->bindTo(null)()
    );
} catch (\Throwable $e) {
    // We'll get an error about using $this is a non-object context
    // This will no longer be possible after PHP 7.4
    var_dump($e);
}

// You can definitely still do this:
class UnrelatedClass { private $items = ["foo", "bar"]; }

var_dump(
    $items->exampleClosure()->bindTo(new UnrelatedClass, UnrelatedClass::class)()
);

// The only thing that could cause problems is:
// methods meant to be called statically in a mixin that were not defined with static:
class SomeMixin
{
    public function range()
    {
        return function ($start, $end) {
            return new static(range($start, $end));
        };
    }
    
    public function staticRange()
    {
        return static function ($start, $end) {
            return new static(range($start, $end));
        };
    }
}

Collection::mixin(new SomeMixin());

// This will error because:
// 1. the above is not defined with static
// 2. The closure is written inside a class
var_dump(Collection::range(0, 10));

// The following will not because the closure was defined with static
var_dump(Collection::staticRange(0, 10));

// Basically the change prevents the creation of methods and closures that can be used as instance and static methods at the same time by dynamically checking $this inside the function.

Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.7: it works Warning: Cannot unbind $this of closure using $this in /in/3OKGT on line 76 object(Error)#2 (7) { ["message":protected]=> string(34) "Value of type null is not callable" ["string":"Error":private]=> string(0) "" ["code":protected]=> int(0) ["file":protected]=> string(9) "/in/3OKGT" ["line":protected]=> int(76) ["trace":"Error":private]=> array(0) { } ["previous":"Error":private]=> NULL } array(2) { [0]=> string(3) "foo" [1]=> string(3) "bar" } object(Collection)#8 (1) { ["items":"Collection":private]=> array(11) { [0]=> int(0) [1]=> int(1) [2]=> int(2) [3]=> int(3) [4]=> int(4) [5]=> int(5) [6]=> int(6) [7]=> int(7) [8]=> int(8) [9]=> int(9) [10]=> int(10) } } object(Collection)#7 (1) { ["items":"Collection":private]=> array(11) { [0]=> int(0) [1]=> int(1) [2]=> int(2) [3]=> int(3) [4]=> int(4) [5]=> int(5) [6]=> int(6) [7]=> int(7) [8]=> int(8) [9]=> int(9) [10]=> int(10) } }
Output for 7.4.0 - 7.4.25, 7.4.27 - 7.4.33: it works Deprecated: Unbinding $this of closure is deprecated in /in/3OKGT on line 76 object(Error)#2 (7) { ["message":protected]=> string(38) "Using $this when not in object context" ["string":"Error":private]=> string(0) "" ["code":protected]=> int(0) ["file":protected]=> string(9) "/in/3OKGT" ["line":protected]=> int(38) ["trace":"Error":private]=> array(1) { [0]=> array(6) { ["file"]=> string(9) "/in/3OKGT" ["line"]=> int(76) ["function"]=> string(9) "{closure}" ["class"]=> string(10) "Collection" ["type"]=> string(2) "::" ["args"]=> array(0) { } } } ["previous":"Error":private]=> NULL } array(2) { [0]=> string(3) "foo" [1]=> string(3) "bar" } object(Collection)#8 (1) { ["items":"Collection":private]=> array(11) { [0]=> int(0) [1]=> int(1) [2]=> int(2) [3]=> int(3) [4]=> int(4) [5]=> int(5) [6]=> int(6) [7]=> int(7) [8]=> int(8) [9]=> int(9) [10]=> int(10) } } object(Collection)#7 (1) { ["items":"Collection":private]=> array(11) { [0]=> int(0) [1]=> int(1) [2]=> int(2) [3]=> int(3) [4]=> int(4) [5]=> int(5) [6]=> int(6) [7]=> int(7) [8]=> int(8) [9]=> int(9) [10]=> int(10) } }
Output for 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.26: it worksobject(Error)#2 (7) { ["message":protected]=> string(38) "Using $this when not in object context" ["string":"Error":private]=> string(0) "" ["code":protected]=> int(0) ["file":protected]=> string(9) "/in/3OKGT" ["line":protected]=> int(38) ["trace":"Error":private]=> array(1) { [0]=> array(6) { ["file"]=> string(9) "/in/3OKGT" ["line"]=> int(76) ["function"]=> string(9) "{closure}" ["class"]=> string(10) "Collection" ["type"]=> string(2) "::" ["args"]=> array(0) { } } } ["previous":"Error":private]=> NULL } array(2) { [0]=> string(3) "foo" [1]=> string(3) "bar" } object(Collection)#8 (1) { ["items":"Collection":private]=> array(11) { [0]=> int(0) [1]=> int(1) [2]=> int(2) [3]=> int(3) [4]=> int(4) [5]=> int(5) [6]=> int(6) [7]=> int(7) [8]=> int(8) [9]=> int(9) [10]=> int(10) } } object(Collection)#7 (1) { ["items":"Collection":private]=> array(11) { [0]=> int(0) [1]=> int(1) [2]=> int(2) [3]=> int(3) [4]=> int(4) [5]=> int(5) [6]=> int(6) [7]=> int(7) [8]=> int(8) [9]=> int(9) [10]=> int(10) } }

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