Always return the same instance of a const

src/Enum.php

@@ -24,6 +24,13 @@ abstract class Enum
      */
     protected $value;
 
+    /**
+     * Enum value instance
+     *
+     * @var mixed
+     */
+    protected static $instances = array();
+
     /**
      * Store existing constants in a static cache per object.
      *
@@ -177,8 +184,15 @@ public static function search($value)
     public static function __callStatic($name, $arguments)
     {
         $array = static::toArray();
+        $class = get_called_class();
         if (isset($array[$name])) {
-            return new static($array[$name]);
+            if (isset(static::$instances[$class][$name])) {
+                return static::$instances[$class][$name];
+            } else {
+                $result = new static($array[$name]);
+                static::$instances[$class][$name] = $result;
+                return $result;
+            }
         }
 
         throw new \BadMethodCallException("No static method or enum constant '$name' in class " . get_called_class());

tests/EnumTest.php

@@ -225,6 +225,17 @@ public function testEquals()
         $this->assertTrue($foo->equals($anotherFoo));
     }
 
+    /**
+     * __callStatic()
+     */
+    public function testSameInstance()
+    {
+        $foo1 = EnumFixture::FOO();
+        $foo2 = EnumFixture::FOO();
+
+        $this->assertSame($foo1, $foo2);
+    }
+
     /**
      * equals()
      */