feat: Add Unlines operation.

docs/pages/api.rst

@@ -1633,6 +1633,27 @@ truthy
 
 Interface: `Truthyable`_
 
+unlines
+~~~~~~~
+
+Create a string from lines.
+
+Interface: `Unlinesable`_
+
+Signature: ``Collection::unlines();``
+
+.. code-block:: php
+
+    $lines = [
+        'The quick brow fox jumps over the lazy dog.',
+        '',
+        'This is another sentence.',
+    ];
+
+    Collection::fromIterable($lines)
+        ->unlines()
+        ->current();
+
 unpack
 ~~~~~~
 
@@ -1895,6 +1916,7 @@ Signature: ``Collection::zip(iterable ...$iterables);``
 .. _TakeWhileable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/TakeWhileable.php
 .. _Transposeable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Transposeable.php
 .. _Truthyable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Truthyable.php
+.. _Unlinesable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Unlinesable.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

spec/loophp/collection/CollectionSpec.php

@@ -2090,6 +2090,27 @@ public function it_can_unfold(): void
             ]);
     }
 
+    public function it_can_unlines(): void
+    {
+        $lines = [
+            'The quick brow fox jumps over the lazy dog.',
+            '',
+            'This is another sentence.',
+        ];
+
+        $string = <<<'EOF'
+The quick brow fox jumps over the lazy dog.
+
+This is another sentence.
+EOF;
+
+        $this::fromIterable($lines)
+            ->unlines()
+            ->shouldIterateAs([
+                2 => $string,
+            ]);
+    }
+
     public function it_can_unpack(): void
     {
         $input = [

src/Collection.php

@@ -94,6 +94,7 @@
 use loophp\collection\Operation\Transpose;
 use loophp\collection\Operation\Truthy;
 use loophp\collection\Operation\Unfold;
+use loophp\collection\Operation\Unlines;
 use loophp\collection\Operation\Unpack;
 use loophp\collection\Operation\Unpair;
 use loophp\collection\Operation\Until;
@@ -761,6 +762,11 @@ public static function unfold(callable $callback, ...$parameters): CollectionInt
         return (new self())->run(Unfold::of()(...$parameters)($callback));
     }
 
+    public function unlines(): CollectionInterface
+    {
+        return $this->run(Unlines::of());
+    }
+
     public function unpack(): CollectionInterface
     {
         return $this->run(Unpack::of());

src/Contract/Collection.php

@@ -87,6 +87,7 @@
 use loophp\collection\Contract\Operation\Transposeable;
 use loophp\collection\Contract\Operation\Truthyable;
 use loophp\collection\Contract\Operation\Unfoldable;
+use loophp\collection\Contract\Operation\Unlinesable;
 use loophp\collection\Contract\Operation\Unpackable;
 use loophp\collection\Contract\Operation\Unpairable;
 use loophp\collection\Contract\Operation\Untilable;
@@ -176,6 +177,7 @@
  * @template-extends Tailable<TKey, T>
  * @template-extends TakeWhileable<TKey, T>
  * @template-extends Transposeable<TKey, T>
+ * @template-extends Unlinesable<TKey, T>
  * @template-extends Unpackable<TKey, T>
  * @template-extends Unpairable<TKey, T>
  * @template-extends Untilable<TKey, T>
@@ -271,6 +273,7 @@ interface Collection extends
     Transposeable,
     Truthyable,
     Unfoldable,
+    Unlinesable,
     Unpackable,
     Unpairable,
     Untilable,

src/Contract/Operation/Unlinesable.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 Unlinesable
+{
+    /**
+     * @psalm-return \loophp\collection\Contract\Collection<TKey, T>
+     */
+    public function unlines(): Collection;
+}

src/Operation/Unlines.php

@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace loophp\collection\Operation;
+
+use Closure;
+use Generator;
+use Iterator;
+
+/**
+ * @psalm-template TKey
+ * @psalm-template TKey of array-key
+ * @psalm-template T
+ *
+ * phpcs:disable Generic.WhiteSpace.ScopeIndent.IncorrectExact
+ */
+final class Unlines extends AbstractOperation
+{
+    /**
+     * @psalm-return Closure(Iterator<TKey, T|string>): Generator<TKey, T|string, mixed, void>
+     */
+    public function __invoke(): Closure
+    {
+        /**
+         * @psalm-param Iterator<TKey, T|string> $iterator
+         *
+         * @psalm-return Generator<TKey, string>
+         */
+        return static function (Iterator $iterator): Generator {
+            /** @psalm-var callable(Iterator<TKey, T|string>): Generator<TKey, string> $implode */
+            $implode = Implode::of()("\n");
+
+            return $implode($iterator);
+        };
+    }
+}