feat: Resultモナドにmatchメソッドを追加し、OkとErrの処理を統一

Fixes #38

Author: endou-mame

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;
 }

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);
+    }
 }

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);
+    }
 }

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'],
+        ];
+    }
+}