guide WIP [skip ci]

docs/guide/structure-controllers.md

@@ -2,7 +2,7 @@ Controllers
 ===========
 
 Controllers are part of the [MVC](http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller) architecture.
-They contain the actual logic about processing requests and generating responses. In particular, after
+They are objects responsible for processing requests and generating responses. In particular, after
 taking over the control from [applications](structure-applications.md), controllers will analyze incoming request data,
 pass them to [models](structure-models.md), inject model results into [views](structure-views.md),
 and finally generate outgoing responses.
@@ -25,14 +25,13 @@ class PostController extends Controller
     public function actionView($id)
     {
         $model = Post::findOne($id);
+        if ($model === null) {
+            throw new NotFoundHttpException;
+        }
 
-        if ($model !== null) {
         return $this->render('view', [
             'model' => $model,
         ]);
-        } else {
-            throw new NotFoundHttpException;
-        }
     }
 
     public function actionCreate()

docs/guide/structure-models.md

 Models
 ======
 
-Models are objects representing business data, rules and logic. They are part of
-the [MVC](http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller) architecture.
+Models are part of the [MVC](http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller) architecture.
+They are objects representing business data, rules and logic.
 
 You can create model classes by extending [[yii\base\Model]] or its child classes. The base class
 [[yii\base\Model]] supports many useful features:
@@ -11,7 +11,7 @@ You can create model classes by extending [[yii\base\Model]] or its child classe
   or array elements;
 * [Attribute labels](#attribute-labels): specify the display labels for attributes;
 * [Massive assignment](#massive-assignment): supports populating multiple attributes in a single step;
-* [Validation](#validation): ensures input data based on the declared validation rules;
+* [Validation rules](#validation-rules): ensures input data based on the declared validation rules;
 * [Data Exporting](#data-exporting): allows model data to be exported in terms of arrays with customizable formats.
 
 The `Model` class is also the base class for more advanced models, such as [Active Record](db-active-record.md).
@@ -82,7 +82,7 @@ override the magic methods such as `__get()`, `__set()` so that the attributes c
 normal object properties.
 
 
-## Attribute Labels <a name="attribute-labels"></a>
+### Attribute Labels <a name="attribute-labels"></a>
 
 When displaying values or getting input for attributes, you often need to display some labels associated
 with attributes. For example, given an attribute named `firstName`, you may want to display a label `First Name`
@@ -171,7 +171,7 @@ $model->scenario = 'login';
 $model = new User(['scenario' => 'login']);
 ```
 
-By default, the scenarios supported by a model are determined by the [validation rules](#validation) declared
+By default, the scenarios supported by a model are determined by the [validation rules](#validation-rules) declared
 in the model. However, you can customize this behavior by overriding the [[yii\base\Model::scenarios()]] method,
 like the following:
 
@@ -197,7 +197,7 @@ class User extends ActiveRecord
 
 The `scenarios()` method returns an array whose keys are the scenario names and values the corresponding
 *active attributes*. An active attribute can be [massively assigned](#massive-assignment) and is subject
-to [validation](#validation). In the above example, the `username` and `password` attributes are active
+to [validation](#validation-rules). In the above example, the `username` and `password` attributes are active
 in the `login` scenario; while in the `register` scenario, `email` is also active besides `username` and `password`.
 
 The default implementation of `scenarios()` will return all scenarios found in the validation rule declaration
@@ -221,12 +221,12 @@ class User extends ActiveRecord
 }
 ```
 
-The scenario feature is primarily used by [validation](#validation) and [massive attribute assignment](#massive-assignment).
+The scenario feature is primarily used by [validation](#validation-rules) and [massive attribute assignment](#massive-assignment).
 You can, however, use it for other purposes. For example, you may declare [attribute labels](#attribute-labels)
 differently based on the current scenario.
 
 
-## Validation <a name="validation"></a>
+## Validation Rules <a name="validation-rules"></a>
 
 When the data for a model is received from end users, it should be validated to make sure it satisfies
 certain rules (called *validation rules*, also known as *business rules*). For example, given a `ContactForm` model,

docs/guide/structure-views.md

-View
-====
+Views
+=====
 
-> Note: This section is under development.
+Views are part of the [MVC](http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller) architecture.
+They are responsible for presenting data to end users. In a Yii application, the view layer is composed by
+[view templates](#view-templates) and [view components](#view-components). The former contains presentational
+code (e.g. HTML), while the latter provides common view-related features and is responsible for turning view
+templates into response content. We often use "views" to refer to view templates.
 
-The view component is an important part of MVC. The view acts as the interface to the application, making it responsible
-for presenting data to end users, displaying forms, and so forth.
+
+## View Templates
+
+You turn a view template into response content by pushing [model](structure-models.md) data into
+the template and rendering it. For example, in the `post/view` action below, the `view` template
+is rendered with the `$model` data. The rendering result is a string which is returned by the action as the response content.
+
+```php
+namespace app\controllers;
+
+use Yii;
+use app\models\Post;
+use yii\web\Controller;
+use yii\web\NotFoundHttpException;
+
+class PostController extends Controller
+{
+    public function actionView($id)
+    {
+        $model = Post::findOne($id);
+        if ($model === null) {
+            throw new NotFoundHttpException;
+        }
+
+        return $this->render('view', [
+            'model' => $model,
+        ]);
+    }
+}
+```
+
+### Rendering Views in Controllers
+
+### Rendering Views in Widgets
+
+### Rendering Views in Views
+
+### View Names
+
+By default, a view template is simply a PHP script file (called *view file*). Like [models](structure-models.md)
+and [controllers](structure-controllers.md), view files are usually organized under the so-called *view paths*.
+For views rendered by controllers that directly belong to an application, they are located under the `@app/views` path.
+
+* applications:
+* modules:
+* controllers:
+* widgets and other components:
+
+When rendering a view template, you can specify it using a view name, a view file path,
+or an [alias](concept-aliases.md) to the view file path.
+
+If a view name is used, it will be resolved into a view file path according to the current
+[[yii\base\View::context|view context]] using one of the following rules:
+
+* If the view name starts with double slashes `//`, the corresponding view file path is considered to be
+  `@app/views/ViewName`. For example, `//site/about` will be resolved into `@app/views/site/about`.
+* If the view name starts with a single slash `/`, the view file path is formed by prefixing the view name
+  with the [[yii\base\Module::viewPath|view path]] of the currently active [module](structure-modules.md).
+  If there is no active module, `@app/views/ViewName` will be used. For example, `/user/create` will be resolved into
+  `@app/modules/user/views/user/create`, if the currently active module is `user`. If there is no active module,
+  the view file path would be `@app/views/user/create`.
+* If the view is rendered with a [[yii\base\View::context|context]], the view file path will be prefixed with
+  the [[yii\base\ViewContextInterface::getViewPath()|view path]]. For example, `site/about` will be resolved
+  into `@app/views/site/about` if the context is the `SiteController`.
+* If a view was previously rendered, the directory containing that view file will be prefixed to
+  the new view name.
+
+
+## Layouts
+
+### Nested Layouts
+
+
+### Accessing Data
+
+## View Components
+
+## Creating Views
+
+### Setting page title
+### Adding meta tags
+### Registering link tags
+### Registering CSS
+### Registering scripts
+### Static Pages
+### Assets
+
+## Alternative Template Engines
 
 
 Basics