From 03613bd00fbd497a630f5bb67b73b737185789e3 Mon Sep 17 00:00:00 2001
From: kakiuchi-shigenao <kakiuchi-shigenao@wiznet.co.jp>
Date: Thu, 8 May 2025 15:43:03 +0900
Subject: [PATCH] =?UTF-8?q?feat:=20Result=E3=83=A2=E3=83=8A=E3=83=89?=
 =?UTF-8?q?=E3=81=ABmatch=E3=83=A1=E3=82=BD=E3=83=83=E3=83=89=E3=82=92?=
 =?UTF-8?q?=E8=BF=BD=E5=8A=A0=E3=81=97=E3=80=81Ok=E3=81=A8Err=E3=81=AE?=
 =?UTF-8?q?=E5=87=A6=E7=90=86=E3=82=92=E7=B5=B1=E4=B8=80=20Fixes=20#38?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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---
 src/Result.php                  | 12 +++++
 src/Result/Err.php              |  6 +++
 src/Result/Ok.php               |  6 +++
 tests/Unit/Result/MatchTest.php | 93 +++++++++++++++++++++++++++++++++
 4 files changed, 117 insertions(+)
 create mode 100644 tests/Unit/Result/MatchTest.php

diff --git a/src/Result.php b/src/Result.php
index 0cf5999..c4cce19 100644
--- a/src/Result.php
+++ b/src/Result.php
@@ -190,4 +190,16 @@ public function ok(): Option;
      * @return Option<E>
      */
     public function err(): Option;
+
+    /**
+     * Applies one of two functions depending on whether the result is Ok or Err.
+     * Comparable to neverthrow's `match` method.
+     *
+     * @template U
+     * @template V
+     * @param  Closure(T): U $okFn  Function to apply if the Result is Ok
+     * @param  Closure(E): V $errFn Function to apply if the Result is Err
+     * @return U|V           The result of applying the appropriate function
+     */
+    public function match(Closure $okFn, Closure $errFn): mixed;
 }
diff --git a/src/Result/Err.php b/src/Result/Err.php
index 35bed4a..02fff8a 100644
--- a/src/Result/Err.php
+++ b/src/Result/Err.php
@@ -245,4 +245,10 @@ public function getIterator(): Traversable
     {
         return new EmptyIterator();
     }
+
+    #[Override]
+    public function match(Closure $okFn, Closure $errFn): mixed
+    {
+        return $errFn($this->value);
+    }
 }
diff --git a/src/Result/Ok.php b/src/Result/Ok.php
index fd3ff57..77aeb9d 100644
--- a/src/Result/Ok.php
+++ b/src/Result/Ok.php
@@ -238,4 +238,10 @@ public function getIterator(): Traversable
     {
         yield $this->value;
     }
+
+    #[Override]
+    public function match(Closure $okFn, Closure $errFn): mixed
+    {
+        return $okFn($this->value);
+    }
 }
diff --git a/tests/Unit/Result/MatchTest.php b/tests/Unit/Result/MatchTest.php
new file mode 100644
index 0000000..4c618a1
--- /dev/null
+++ b/tests/Unit/Result/MatchTest.php
@@ -0,0 +1,93 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WizDevelop\PhpMonad\Tests\Unit\Result;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\Attributes\TestDox;
+use WizDevelop\PhpMonad\Result;
+use WizDevelop\PhpMonad\Tests\Assert;
+use WizDevelop\PhpMonad\Tests\TestCase;
+
+#[TestDox('Result - MatchTest')]
+#[CoversClass(Result::class)]
+final class MatchTest extends TestCase
+{
+    /**
+     * @return Result<int, string>
+     */
+    public function createResult(): Result
+    {
+        return Result\ok(42);
+    }
+
+    /**
+     * @template T
+     * @template E
+     * @template U
+     * @param Result<T, E> $result
+     * @param U            $okValue       Value to return when Result is Ok
+     * @param U            $errValue      Value to return when Result is Err
+     * @param U            $expected      Expected outcome
+     * @param array<T|E>   $expectedCalls Values that should be passed to the callbacks
+     */
+    #[Test]
+    #[TestDox('match test')]
+    #[DataProvider('matchMatrix')]
+    public function match(
+        Result $result,
+        mixed $okValue,
+        mixed $errValue,
+        mixed $expected,
+        array $expectedCalls
+    ): void {
+        $calls = [];
+
+        $actual = $result->match(
+            static function (mixed $value) use ($okValue, &$calls): mixed {
+                $calls[] = $value;
+
+                return $okValue;
+            },
+            static function (mixed $value) use ($errValue, &$calls): mixed {
+                $calls[] = $value;
+
+                return $errValue;
+            }
+        );
+
+        Assert::assertSame($expected, $actual);
+        Assert::assertSame($expectedCalls, $calls);
+    }
+
+    /**
+     * @return iterable<array{
+     *   Result\Ok<int>|Result\Err<string>,
+     *   string,
+     *   string,
+     *   string,
+     *   array<int|string>
+     * }>
+     */
+    public static function matchMatrix(): iterable
+    {
+        yield 'ok' => [
+            Result\ok(42),
+            'success',
+            'failure',
+            'success',
+            [42],
+        ];
+
+        yield 'err' => [
+            Result\err('error'),
+            'success',
+            'failure',
+            'failure',
+            ['error'],
+        ];
+    }
+}