[Functional] Add Either::getOrThrow method.

Author: whsv26

src/Fp/Functional/Either/Either.php

@@ -65,6 +65,25 @@ public function getOrCall(callable $fallback): mixed
             : $fallback();
     }
 
+    /**
+     * ```php
+     * >>> Either::right(1)->getOrThrow(fn($err) => new RuntimeException($err));
+     * => 1
+     *
+     * >>> Either::left('error')->getOrThrow(fn($err) => new RuntimeException($err));
+     * RuntimeException with message 'error'
+     * ```
+     *
+     * @psalm-param callable(L): Throwable $fallback
+     * @psalm-return R
+     */
+    public function getOrThrow(callable $fallback): mixed
+    {
+        return $this->isRight()
+            ? $this->value
+            : throw $fallback($this->value);
+    }
+
     /**
      * Combine two Either into one
      *

tests/Runtime/Classes/Either/EitherTest.php

@@ -11,6 +11,7 @@
 use Fp\Functional\Validated\Invalid;
 use Fp\Functional\Validated\Valid;
 use PHPUnit\Framework\TestCase;
+use RuntimeException;
 
 final class EitherTest extends TestCase
 {
@@ -136,10 +137,21 @@ public function testGetOrElse(): void
     {
         $this->assertEquals(1, Either::right(1)->getOrElse(0));
         $this->assertEquals(0, Either::left('err')->getOrElse(0));
+    }
+
+    public function testGetOrCall(): void
+    {
         $this->assertEquals(1, Either::right(1)->getOrCall(fn() => 0));
         $this->assertEquals(0, Either::left('err')->getOrCall(fn() => 0));
     }
 
+    public function testGetOrThrow(): void
+    {
+        $this->assertEquals(1, Either::right(1)->getOrThrow(fn($err) => new RuntimeException($err)));
+        $this->expectExceptionMessage('err');
+        Either::left('err')->getOrThrow(fn($err) => new RuntimeException($err));
+    }
+
     public function testOrElse(): void
     {
         $this->assertEquals(