Add Unpack operation.

docs/pages/api.rst

@@ -1273,6 +1273,28 @@ Signature: ``Collection::transpose();``
     $result = Collection::with($records)
         ->transpose();
 
+unpack
+~~~~~~
+
+Unpack items.
+
+Interface: `Unpackable`_
+
+Signature: ``Collection::unpack();``
+
+.. code-block:: php
+
+    $input = [['a', 'b'], ['c', 'd'], ['e', 'f']];
+
+    $c = Collection::fromIterable($input)
+        ->unpack();
+
+    // [
+    //     ['a' => 'b'],
+    //     ['c' => 'd'],
+    //     ['e' => 'f'],
+    // ];
+
 unpair
 ~~~~~~
 
@@ -1508,6 +1530,7 @@ Interface: `Truthyable`_
 .. _Nthable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Nthable.php
 .. _Nullsyable: https://github.com/loophp/collection/blob/master/src/Contract/Transformation/Nullsyable.php
 .. _Onlyable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Onlyable.php
+.. _Packable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Packable.php
 .. _Padable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Padable.php
 .. _Pairable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Pairable.php
 .. _Permutateable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Permutateable.php
@@ -1529,7 +1552,8 @@ Interface: `Truthyable`_
 .. _Transformable: https://github.com/loophp/collection/blob/master/src/Contract/Transformation/Transformable.php
 .. _Transposeable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Transposeable.php
 .. _Truthyable: https://github.com/loophp/collection/blob/master/src/Contract/Transformation/Truthyable.php
-.. _Unpair: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Unpairable.php
+.. _Unpackable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Unpackagle.php
+.. _Unpairable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Unpairable.php
 .. _Untilable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Untilable.php
 .. _Unwrapable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Unwrapable.php
 .. _Windowable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Windowable.php

spec/loophp/collection/CollectionSpec.php

@@ -1896,6 +1896,45 @@ public function it_can_truthy(): void
             ->shouldReturn(false);
     }
 
+    public function it_can_unpack(): void
+    {
+        $input = [
+            ['a', 'a'],
+            ['b', 'b'],
+            ['c', 'c'],
+            ['d', 'd'],
+            ['e', 'e'],
+            'bar',
+        ];
+
+        $this::fromIterable($input)
+            ->unpack()
+            ->shouldIterateAs([
+                'a' => 'a',
+                'b' => 'b',
+                'c' => 'c',
+                'd' => 'd',
+                'e' => 'e',
+            ]);
+
+        $input = [
+            ['a', 'b', 'c' => 'c', 'd' => 'd'],
+            ['e', 'f', 'g' => 'g', 'h' => 'h'],
+            ['i', 'j'],
+            'foo',
+        ];
+
+        $this::fromIterable($input)
+            ->unpack()
+            ->shouldIterateAs([
+                'a' => 'b',
+                'c' => 'd',
+                'e' => 'f',
+                'g' => 'h',
+                'i' => 'j',
+            ]);
+    }
+
     public function it_can_unpair(): void
     {
         $input = [

src/Collection.php

@@ -71,6 +71,7 @@
 use loophp\collection\Operation\Tail;
 use loophp\collection\Operation\Times;
 use loophp\collection\Operation\Transpose;
+use loophp\collection\Operation\Unpack;
 use loophp\collection\Operation\Unpair;
 use loophp\collection\Operation\Until;
 use loophp\collection\Operation\Unwrap;
@@ -648,6 +649,11 @@ public function truthy(): bool
         return $this->transform(new Truthy());
     }
 
+    public function unpack(): CollectionInterface
+    {
+        return $this->run(new Unpack());
+    }
+
     public function unpair(): CollectionInterface
     {
         return $this->run(new Unpair());

src/Contract/Operation/Unpackable.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace loophp\collection\Contract\Operation;
+
+use loophp\collection\Contract\Collection;
+
+/**
+ * @psalm-template TKey
+ * @psalm-template TKey of array-key
+ * @psalm-template T
+ */
+interface Unpackable
+{
+    /**
+     * @return \loophp\collection\Contract\Collection<TKey, T>
+     */
+    public function unpack(): Collection;
+}

src/Operation/Unpack.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace loophp\collection\Operation;
+
+use Closure;
+use Generator;
+use Iterator;
+use loophp\collection\Contract\Operation;
+use loophp\collection\Iterator\IterableIterator;
+use loophp\collection\Transformation\Run;
+
+/**
+ * @psalm-template TKey
+ * @psalm-template TKey of array-key
+ * @psalm-template T
+ */
+final class Unpack extends AbstractOperation implements Operation
+{
+    public function __invoke(): Closure
+    {
+        return
+            /**
+             * @psalm-param Iterator<int, array{0:TKey, 1:T}|T> $iterator
+             *
+             * @psalm-return Generator<TKey, T>
+             */
+            static function (Iterator $iterator): Generator {
+                foreach ($iterator as $key => $value) {
+                    if (!is_iterable($value)) {
+                        continue;
+                    }
+
+                    /** @psalm-var array<int, array<TKey, T>> $chunks */
+                    $chunks = (new Run((new Chunk(2))))(new IterableIterator($value));
+
+                    foreach ($chunks as [$k, $v]) {
+                        yield $k => $v;
+                    }
+                }
+            };
+    }
+}