├── composer.json
└── src
    ├── CartesianProduct.php
    └── function.php


/composer.json:
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 1 | {
 2 |     "name": "bentools/cartesian-product",
 3 |     "description": "A simple, low-memory footprint function to generate all combinations from a multi-dimensionnal array.",
 4 |     "type": "library",
 5 |     "license": "MIT",
 6 |     "autoload": {
 7 |         "psr-4": {
 8 |             "BenTools\\CartesianProduct\\" : "src"
 9 |         },
10 |         "files": ["src/function.php"]
11 |     },
12 |     "autoload-dev": {
13 |         "psr-4": {
14 |             "BenTools\\CartesianProduct\\Tests\\" : "tests"
15 |         },
16 |         "files": [
17 |             "vendor/symfony/var-dumper/Resources/functions/dump.php"
18 |         ]
19 |     },
20 |     "require": {
21 |         "php": ">=7.4"
22 |     },
23 |     "require-dev": {
24 |         "phpunit/phpunit": "^8.0|^9.0",
25 |         "squizlabs/php_codesniffer": "@stable",
26 |         "php-coveralls/php-coveralls": "@stable",
27 |         "symfony/var-dumper": "^3.2|^4.0",
28 |         "dms/phpunit-arraysubset-asserts": "^0.3.1"
29 |     }
30 | }
31 | 


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/src/CartesianProduct.php:
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  1 | <?php
  2 | 
  3 | namespace BenTools\CartesianProduct;
  4 | 
  5 | use Countable;
  6 | use InvalidArgumentException;
  7 | use IteratorAggregate;
  8 | use Traversable;
  9 | 
 10 | class CartesianProduct implements IteratorAggregate, Countable
 11 | {
 12 |     /**
 13 |      * @var array
 14 |      */
 15 |     private $set = [];
 16 | 
 17 |     /**
 18 |      * @var bool
 19 |      */
 20 |     private $isRecursiveStep = false;
 21 | 
 22 |     /**
 23 |      * @var int
 24 |      */
 25 |     private $count;
 26 | 
 27 |     /**
 28 |      * CartesianProduct constructor.
 29 |      *
 30 |      * @param array $set - A multidimensionnal array.
 31 |      */
 32 |     public function __construct(array $set)
 33 |     {
 34 |         $this->set = $set;
 35 |     }
 36 | 
 37 |     /**
 38 |      * @return \Traversable
 39 |      */
 40 |     public function getIterator(): Traversable
 41 |     {
 42 |         if ([] === $this->set) {
 43 |             if (true === $this->isRecursiveStep) {
 44 |                 yield [];
 45 |             }
 46 | 
 47 |             return;
 48 |         }
 49 | 
 50 |         $set = $this->set;
 51 |         $keys = \array_keys($set);
 52 |         $last = \end($keys);
 53 |         $subset = \array_pop($set);
 54 |         $this->validate($subset, $last);
 55 |         foreach (self::subset($set) as $product) {
 56 |             foreach ($subset as $value) {
 57 |                 yield $product + [$last => ($value instanceof \Closure ? $value($product) : $value)];
 58 |             }
 59 |         }
 60 |     }
 61 | 
 62 |     /**
 63 |      * @param $subset
 64 |      * @param $key
 65 |      */
 66 |     private function validate($subset, $key)
 67 |     {
 68 |         // Validate array subset
 69 |         if (\is_array($subset) && !empty($subset)) {
 70 |             return;
 71 |         }
 72 | 
 73 |         // Validate iterator subset
 74 |         if ($subset instanceof Traversable && $subset instanceof Countable && \count($subset) > 0) {
 75 |             return;
 76 |         }
 77 | 
 78 |         throw new InvalidArgumentException(\sprintf('Key "%s" should return a non-empty iterable', $key));
 79 |     }
 80 | 
 81 |     /**
 82 |      * @param  array $subset
 83 |      * @return CartesianProduct
 84 |      */
 85 |     private static function subset(array $subset)
 86 |     {
 87 |         $product = new self($subset);
 88 |         $product->isRecursiveStep = true;
 89 |         return $product;
 90 |     }
 91 | 
 92 |     /**
 93 |      * @return array
 94 |      */
 95 |     public function asArray()
 96 |     {
 97 |         return \iterator_to_array($this);
 98 |     }
 99 | 
100 |     /**
101 |      * @return int
102 |      */
103 |     public function count(): int
104 |     {
105 |         if (null === $this->count) {
106 |             $this->count = (int) \array_product(
107 |                 \array_map(
108 |                     function ($subset, $key) {
109 |                         $this->validate($subset, $key);
110 |                         return \count($subset);
111 |                     },
112 |                     $this->set,
113 |                     \array_keys($this->set)
114 |                 )
115 |             );
116 |         }
117 |         return $this->count;
118 |     }
119 | }
120 | 


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/src/function.php:
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 1 | <?php
 2 | 
 3 | namespace BenTools\CartesianProduct;
 4 | 
 5 | require_once __DIR__ . '/CartesianProduct.php';
 6 | 
 7 | /**
 8 |  * @param  array $set - A multidimensionnal array.
 9 |  * @return CartesianProduct
10 |  */
11 | function cartesian_product(array $set)
12 | {
13 |     return new CartesianProduct($set);
14 | }
15 | 


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