fix: foldleft operation

Simplify
Documentation update

docs/pages/api.rst

@@ -944,25 +944,18 @@ This example will return ``['a', 'b', 'c', 'd', 'a']``.
 foldLeft
 ~~~~~~~~
 
-Takes the initial value and the first item of the list and applies the function
-to them, then feeds the function with this result and the second argument and so
-on. See ``scanLeft`` for intermediate results.
-
-Interface: `FoldLeftable`_
+Takes the initial value and the first item of the collection and applies the
+function to them, then feeds the function with this result and the second
+argument and so on. See ``scanLeft`` for intermediate results.
 
-Signature: ``Collection::foldLeft(callable $callback, $initial): mixed;``
+When the collection is empty, the initial value is returned.
 
-.. code-block:: php
+Interface: `FoldLeftable`_
 
-    Collection::fromIterable(range('A', 'C'))
-        ->foldLeft(
-            static function (string $carry, string $item): string {
-                $carry .= $item;
+Signature: ``Collection::foldLeft(callable $callback, mixed $initial): mixed;``
 
-                return $carry;
-            },
-            ''
-        ); // 'ABC'
+.. literalinclude:: code/operations/foldleft.php
+  :language: php
 
 foldLeft1
 ~~~~~~~~~
@@ -1800,7 +1793,7 @@ When the collection is empty, the initial value is returned.
 
 Interface: `Reduceable`_
 
-Signature: ``Collection::reduce(callable $callback, $initial = null): mixed;``
+Signature: ``Collection::reduce(callable $callback, mixed $initial = null): mixed;``
 
 .. literalinclude:: code/operations/reduce.php
   :language: php

docs/pages/code/operations/compare.php

@@ -15,7 +15,12 @@
     ? $left
     : $right;
 
-$result = Collection::fromIterable([(object) ['id' => 2, 'age' => 5], (object) ['id' => 1, 'age' => 10]])
+$input = [
+    (object) ['id' => 2, 'age' => 5],
+    (object) ['id' => 1, 'age' => 10],
+];
+
+$result = Collection::fromIterable($input)
     ->compare($callback); // (object) ['id' => 1, 'age' => 10]
 
 $result = Collection::empty()

docs/pages/code/operations/foldleft.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App;
+
+use loophp\collection\Collection;
+
+include __DIR__ . '/../../../../vendor/autoload.php';
+
+$callback = static fn (int $carry, int $item): int => $carry + $item;
+
+$collection = Collection::fromIterable(range(1, 5))
+    ->foldLeft($callback, 0); // 15
+
+$collection = Collection::empty()
+    ->foldLeft($callback, 'foo'); // 'foo'

docs/pages/code/operations/reduce.php

@@ -10,8 +10,11 @@
 
 $callback = static fn (int $carry, int $item): int => $carry + $item;
 
-$collection = Collection::empty()
-    ->reduce($callback); // null
-
 $collection = Collection::fromIterable(range(1, 5))
     ->reduce($callback, 0); // 15
+
+$collection = Collection::empty()
+    ->reduce($callback, 'foo'); // 'foo'
+
+$collection = Collection::empty()
+    ->reduce($callback); // null

phpstan-baseline.neon

@@ -200,11 +200,6 @@ parameters:
 			count: 1
 			path: src/Operation/FoldLeft.php
 
-		-
-			message: "#^Template type W of method loophp\\\\collection\\\\Operation\\\\FoldLeft\\:\\:__invoke\\(\\) is not referenced in a parameter\\.$#"
-			count: 1
-			path: src/Operation/FoldLeft.php
-
 		-
 			message: "#^Template type V of method loophp\\\\collection\\\\Operation\\\\FoldLeft1\\:\\:__invoke\\(\\) is not referenced in a parameter\\.$#"
 			count: 1

src/Contract/Operation/FoldLeftable.php

@@ -17,12 +17,11 @@ interface FoldLeftable
      * @see https://loophp-collection.readthedocs.io/en/stable/pages/api.html#foldleft
      *
      * @template V
-     * @template W
      *
-     * @param callable((V|W), T, TKey, iterable<TKey, T>): W $callback
+     * @param callable(V, T, TKey, iterable<TKey, T>): V $callback
      * @param V $initial
      *
-     * @return V|W
+     * @return V
      */
     public function foldLeft(callable $callback, mixed $initial): mixed;
 }

src/Operation/FoldLeft.php

@@ -6,6 +6,7 @@
 
 use Closure;
 use Generator;
+use loophp\iterators\ReduceIterableAggregate;
 
 /**
  * @immutable
@@ -17,33 +18,29 @@ final class FoldLeft extends AbstractOperation
 {
     /**
      * @template V
-     * @template W
      *
-     * @return Closure(callable((V|W), T, TKey, iterable<TKey, T>): W): Closure(V): Closure(iterable<TKey, T>): Generator<TKey, V|W>
+     * @return Closure(callable(V, T, TKey, iterable<TKey, T>): V): Closure(V): Closure(iterable<TKey, T>): Generator<int, V>
      */
     public function __invoke(): Closure
     {
         return
             /**
-             * @param callable((V|W), T, TKey, iterable<TKey, T>): W $callback
+             * @param callable(V, T, TKey, iterable<TKey, T>): V $callback
              *
-             * @return Closure(V): Closure(iterable<TKey, T>): Generator<TKey, V|W>
+             * @return Closure(V): Closure(iterable<TKey, T>): Generator<int, V>
              */
             static fn (callable $callback): Closure =>
                 /**
                  * @param V $initial
                  *
-                 * @return Closure(iterable<TKey, T>): Generator<TKey, V|W>
+                 * @return Closure(iterable<TKey, T>): Generator<int, V>
                  */
-                static function (mixed $initial) use ($callback): Closure {
-                    /** @var Closure(iterable<TKey, T>): Generator<TKey, V|W> $pipe */
-                    $pipe = (new Pipe())()(
-                        (new ScanLeft())()($callback)($initial),
-                        (new Last())()
-                    );
-
-                    // Point free style.
-                    return $pipe;
-                };
+                static fn (mixed $initial): Closure =>
+                    /**
+                     * @param iterable<TKey, T> $iterable
+                     *
+                     * @return Generator<int, V>
+                     */
+                    static fn (iterable $iterable): Generator => yield from new ReduceIterableAggregate($iterable, Closure::fromCallable($callback), $initial);
     }
 }