Add new object syntax for the not_in validation rule

src/Illuminate/Validation/Rule.php

@@ -38,6 +38,17 @@ public static function in(array $values)
         return new Rules\In($values);
     }
 
+    /**
+     * Get a not_in constraint builder instance.
+     *
+     * @param  array  $values
+     * @return \Illuminate\Validation\Rules\In
+     */
+    public static function notIn(array $values)
+    {
+        return new Rules\NotIn($values);
+    }
+
     /**
      * Get a unique constraint builder instance.
      *

src/Illuminate/Validation/Rules/In.php

@@ -4,6 +4,11 @@
 
 class In
 {
+    /**
+     * The name of the rule.
+     */
+    protected $rule = 'in';
+
     /**
      * The accepted values.
      *
@@ -29,6 +34,6 @@ public function __construct(array $values)
      */
     public function __toString()
     {
-        return 'in:'.implode(',', $this->values);
+        return $this->rule.':'.implode(',', $this->values);
     }
 }

src/Illuminate/Validation/Rules/NotIn.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Illuminate\Validation\Rules;
+
+class NotIn extends In
+{
+    /**
+     * The name of the rule.
+     */
+    protected $rule = 'not_in';
+}

tests/Validation/ValidationNotInRuleTest.php

@@ -0,0 +1,18 @@
+<?php
+
+use Illuminate\Validation\Rule;
+use Illuminate\Validation\Rules\NotIn;
+
+class ValidationNotInRuleTest extends PHPUnit_Framework_TestCase
+{
+    public function testItCorrectlyFormatsAStringVersionOfTheRule()
+    {
+        $rule = new NotIn(['Laravel', 'Framework', 'PHP']);
+
+        $this->assertEquals('not_in:Laravel,Framework,PHP', (string) $rule);
+
+        $rule = Rule::notIn([1, 2, 3, 4]);
+
+        $this->assertEquals('not_in:1,2,3,4', (string) $rule);
+    }
+}