allow a closure for the result parameter

README.md

@@ -348,6 +348,11 @@ So you can use it like:
 
 ```php
 Entrust::routeNeedsRole('admin/advanced*', 'owner', Redirect::to('/home'));
+
+// You may use a closure for the result parameter which will only be executed when access is denied.
+Entrust::routeNeedsRole('admin/advanced*', 'owner', function () {
+    Redirect::to('/home')->withErrors('Access Denied');
+});
 ```
 
 Furthermore both of these methods accept a fourth parameter.

src/Entrust/Entrust.php

@@ -93,6 +93,10 @@ public function routeNeedsRole($route, $roles, $result = null, $requireAll = tru
             $hasRole = $this->hasRole($roles, $requireAll);
 
             if (!$hasRole) {
+                // if result is a closure, then call it and use the returned value
+                if (!empty($result) && !is_string($result) && is_callable($result)) {
+                    $result = $result();
+                }
                 return empty($result) ? $this->app->abort(403) : $result;
             }
         };
@@ -127,6 +131,10 @@ public function routeNeedsPermission($route, $permissions, $result = null, $requ
             $hasPerm = $this->can($permissions, $requireAll);
 
             if (!$hasPerm) {
+                // if result is a closure, then call it and use the returned value
+                if (!empty($result) && !is_string($result) && is_callable($result)) {
+                    $result = $result();
+                }
                 return empty($result) ? $this->app->abort(403) : $result;
             }
         };
@@ -170,6 +178,10 @@ public function routeNeedsRoleOrPermission($route, $roles, $permissions, $result
             }
 
             if (!$hasRolePerm) {
+                // if result is a closure, then call it and use the returned value
+                if (!empty($result) && !is_string($result) && is_callable($result)) {
+                    $result = $result();
+                }
                 return empty($result) ? $this->app->abort(403) : $result;
             }
         };