Merge branch 'develop'

* develop:
  specify release number
  build a Maybe out of an Either

Author: Baptouuuu

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## 4.3.0 - 2022-07-02
+
+### Added
+
+- `Innmind\Immutable\Either::maybe()`
+
 ## 4.2.0 - 2022-03-26
 
 ### Added

docs/EITHER.md

@@ -138,3 +138,18 @@ This is similar to the `->map()` function but will be applied on the left value
 $either = identify($request)
     ->leftMap(fn(Error $error) => new ErrorResponse($error));
 ```
+
+## `->maybe()`
+
+This returns a [`Maybe`](MAYBE.md) containing the right value, in case of a left value it returns a `Maybe` with nothing inside.
+
+```php
+Either::right('something')->maybe()->match(
+    static fn($value) => $value,
+    static fn() => null,
+); // returns 'something'
+Either::left('something')->maybe()->match(
+    static fn($value) => $value,
+    static fn() => null,
+); // returns null
+```

src/Either.php

@@ -130,4 +130,12 @@ public function filter(callable $predicate, callable $otherwise): self
     {
         return new self($this->either->filter($predicate, $otherwise));
     }
+
+    /**
+     * @return Maybe<R>
+     */
+    public function maybe(): Maybe
+    {
+        return $this->either->maybe();
+    }
 }

src/Either/Implementation.php

@@ -3,7 +3,10 @@
 
 namespace Innmind\Immutable\Either;
 
-use Innmind\Immutable\Either;
+use Innmind\Immutable\{
+    Either,
+    Maybe,
+};
 
 /**
  * @template L
@@ -70,4 +73,9 @@ public function otherwise(callable $otherwise): Either;
      * @return self<L|A, R>
      */
     public function filter(callable $predicate, callable $otherwise): self;
+
+    /**
+     * @return Maybe<R>
+     */
+    public function maybe(): Maybe;
 }

src/Either/Left.php

@@ -3,7 +3,10 @@
 
 namespace Innmind\Immutable\Either;
 
-use Innmind\Immutable\Either;
+use Innmind\Immutable\{
+    Either,
+    Maybe,
+};
 
 /**
  * @template L1
@@ -62,4 +65,9 @@ public function filter(callable $predicate, callable $otherwise): self
     {
         return $this;
     }
+
+    public function maybe(): Maybe
+    {
+        return Maybe::nothing();
+    }
 }

src/Either/Right.php

@@ -3,7 +3,10 @@
 
 namespace Innmind\Immutable\Either;
 
-use Innmind\Immutable\Either;
+use Innmind\Immutable\{
+    Either,
+    Maybe,
+};
 
 /**
  * @template L1
@@ -66,4 +69,9 @@ public function filter(callable $predicate, callable $otherwise): Implementation
 
         return new Left($otherwise());
     }
+
+    public function maybe(): Maybe
+    {
+        return Maybe::just($this->value);
+    }
 }

tests/EitherTest.php

@@ -328,4 +328,28 @@ public function testLeftValueIsLeftMapped()
                 );
             });
     }
+
+    public function testMaybe()
+    {
+        $this
+            ->forAll(
+                Set\AnyType::any(),
+                Set\AnyType::any(),
+            )
+            ->then(function($left, $right) {
+                $this->assertSame(
+                    $right,
+                    Either::right($right)->maybe()->match(
+                        static fn($value) => $value,
+                        static fn() => null,
+                    ),
+                );
+                $this->assertNull(
+                    Either::left($left)->maybe()->match(
+                        static fn($value) => $value,
+                        static fn() => null,
+                    ),
+                );
+            });
+    }
 }