[1.x] Add ability to resolve feature instance. (#118)

* Enable retrieval of feature implementation

* Formatting

src/Drivers/Decorator.php

@@ -72,6 +72,13 @@ class Decorator implements CanListStoredFeatures, Driver
      */
     protected $cache;
 
+    /**
+     * Map of feature names to their implementations.
+     *
+     * @var array<string, mixed>
+     */
+    protected $nameMap = [];
+
     /**
      * Create a new driver decorator instance.
      *
@@ -122,6 +129,10 @@ public function define($feature, $resolver = null): void
                 $this->container->make($feature)->name ?? $feature,
                 new LazilyResolvedFeature($feature),
             ];
+
+            $this->nameMap[$feature] = $resolver->feature;
+        } else {
+            $this->nameMap[$feature] = $resolver;
         }
 
         $this->driver->define($feature, function ($scope) use ($feature, $resolver) {
@@ -488,6 +499,27 @@ public function name($feature)
         return $this->resolveFeature($feature);
     }
 
+    /**
+     * Retrieve the feature's class.
+     *
+     * @param  string  $feature
+     * @return mixed
+     */
+    public function instance($name)
+    {
+        $feature = $this->nameMap[$name] ?? $name;
+
+        if (is_string($feature) && class_exists($feature)) {
+            return $this->container->make($feature);
+        }
+
+        if ($feature instanceof Closure || $feature instanceof Lottery) {
+            return $feature;
+        }
+
+        return fn () => $feature;
+    }
+
     /**
      * Resolve the feature name and ensure it is defined.
      *

tests/Feature/ArrayDriverTest.php

@@ -2,6 +2,7 @@
 
 namespace Tests\Feature;
 
+use Closure;
 use Illuminate\Container\Container;
 use Illuminate\Support\Facades\Auth;
 use Illuminate\Support\Facades\Config;
@@ -1154,6 +1155,29 @@ public function test_it_can_list_stored_features()
 
         $this->assertSame(Feature::stored(), ['bar']);
     }
+
+    public function test_it_can_resolve_feature_instance()
+    {
+        Feature::define(MyFeature::class);
+        $this->assertInstanceOf(MyFeature::class, Feature::instance('my-feature'));
+        $this->assertInstanceOf(MyFeature::class, Feature::instance(MyFeature::class));
+
+        Feature::define(MyUnnamedFeature::class);
+        $this->assertInstanceOf(MyUnnamedFeature::class, Feature::instance(MyUnnamedFeature::class));
+
+        Feature::define('closure-based-feature', $closure = fn () => true);
+        $this->assertSame($closure, Feature::instance('closure-based-feature'));
+
+        Feature::define('value-based-feature', '123');
+        $feature = Feature::instance('value-based-feature');
+        $this->assertInstanceOf(Closure::class, $feature);
+        $this->assertSame('123', $feature());
+
+        Feature::define('lottery-based-feature', Lottery::odds(1, 1)->winner(fn () => '345'));
+        $feature = Feature::instance('lottery-based-feature');
+        $this->assertInstanceOf(Lottery::class, $feature);
+        $this->assertSame('345', $feature());
+    }
 }
 
 class MyFeature