> For the complete documentation index, see [llms.txt](https://eucalypt.gitbook.io/eucalypt/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://eucalypt.gitbook.io/eucalypt/features/views/layouts.md).

# Layouts

### Location

The view layout files are located in the `app/views/layouts` directory.

### Default <a href="#default" id="default"></a>

The default layout is set to be `main.erb`, which is a file that is already included in Eucalypt. However, this can be changed in the [core application file](/eucalypt/features/core-application-file.md).

{% code title="app/views/layouts/main.rb" %}

```markup
<html>
    <head>
        <title><%= @page_title %></title>
        <%= manifest :stylesheet, :script %>    
    </head>
    <body>
        <%= yield %>
    </body>
</html>
```

{% endcode %}

**NOTE**: `manifest` is an [in-built helper method for including the manifest stylesheet and javascript files](/eucalypt/features/manifest-accessor.md).

Observe the `yield` method - this is **essential** to include in any layout file, as it specifies where the rendered content should be placed in the view.

### Example

Suppose we have an index page that says `Hello World!`:

{% code title="app/views/index.erb" %}

```markup
<h1>Hello World!</h1>
```

{% endcode %}

But this isn't a complete webpage without the `html`, `body` and `head` tags (which were in the `main.erb` layout).

If we were to render the index page by inserting the contents of `index.erb` into the location of the `yield` method call in `main.erb`, and set the instance variable `@page_title` to `'Welcome to the welcome page!'`, we would have a perfect webpage that looks like:

```markup
<html>
    <head>
        <title>Welcome to the welcome page!</title>
        <%= manifest :stylesheet, :script %>
    </head>
    <body>
        <h1>Hello World!</h1>
    </body>
</html>
```

To render the `index.erb` file using the `main.erb` file as a layout (whenever we visit `/`, `/index` or `/home`), simply add the following resource handler in your controller:

```ruby
get '/' do
  @page_title = 'Welcome to the welcome page!'
  erb :index, layout: :'layouts/main'
end
```

But remember, since the default layout is `main.erb`, we don't need to specify the layout.&#x20;

This means we can get rid of the `layout` keyword argument to the `erb` rendering method, along with the `:'layouts/main'` symbol that specifies the layout:

```ruby
get '/' do
  @page_title = 'Welcome to the welcome page!'
  erb :index
end
```

### Don't want a layout?

For some views, you might want to render the entire page from a single view file (without a layout). This is often the case with pages that are unique and don't follow a pattern like having the same navigation bar as other pages. Such page examples are typically index pages, 404 pages etc.

To omit a layout, simply set `false` as the keyword argument `layout:`:

```ruby
error Sinatra::NotFound do 
  erb :"404", layout: false
end
```