add IOMonadOps

Author: Jaco Labuschagne

src/IOMonadOps.php

@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Zodimo\BaseReturn;
+
+class IOMonadOps
+{
+    /**
+     * @template VALUE
+     * @template ERR
+     *
+     * @param array<IOMonad<VALUE,ERR>> $values
+     *
+     * @return IOMonad<array<VALUE>, ERR>
+     */
+    public static function sequence(array $values): IOMonad
+    {
+        // sequence :: Monad m => Either a (m a0) -> m (Either a a0)
+        // list of values or first error
+        $output = [];
+        foreach ($values as $value) {
+            /**
+             * @var IOMonad<VALUE,ERR> $value
+             */
+            if ($value->isFailure()) {
+                return $value;
+            }
+            // @phpstan-ignore method.void
+            $output[] = $value->unwrapSuccess(function () {});
+        }
+
+        // @phpstan-ignore return.type
+        return IOMonad::pure($output);
+    }
+}

tests/Unit/IOMonadOpsTest.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Zodimo\BaseReturn\Tests\Unit;
+
+use PHPUnit\Framework\TestCase;
+use Zodimo\BaseReturn\IOMonad;
+use Zodimo\BaseReturn\IOMonadOps;
+use Zodimo\BaseReturnTest\MockClosureTrait;
+
+/**
+ * @internal
+ *
+ * @coversNothing
+ */
+class IOMonadOpsTest extends TestCase
+{
+    use MockClosureTrait;
+
+    public function testSequenceEmptyList(): void
+    {
+        // @phpstan-ignore argument.templateType, argument.templateType
+        $this->assertEquals([], IOMonadOps::sequence([])->unwrapSuccess($this->createClosureNotCalled()));
+    }
+
+    public function testSequenceValidList(): void
+    {
+        $input = [
+            IOMonad::pure(1),
+            IOMonad::pure(2),
+            IOMonad::pure(3),
+        ];
+
+        $this->assertEquals([1, 2, 3], IOMonadOps::sequence($input)->unwrapSuccess($this->createClosureNotCalled()));
+    }
+
+    public function testSequenceReturnFirstErrorInList(): void
+    {
+        $error = new \RuntimeException('error');
+        $input = [
+            IOMonad::pure(1),
+            IOMonad::fail($error),
+            IOMonad::pure(new \InvalidArgumentException('error')),
+        ];
+
+        // @phpstan-ignore argument.type
+        $this->assertSame($error, IOMonadOps::sequence($input)->unwrapFailure($this->createClosureNotCalled()));
+    }
+}