What does "! []" Elm code syntax in Todomvc mean : <p>Coming from react, I am learning to understand Elm.</p>

<p>In the <a href="https://github.com/evancz/elm-todomvc/blob/master/Todo.elm">Todomvc example code</a>, there is the following code snippet:</p>

<pre><code>-- How we update our Model on a given Msg?
update : Msg -&gt; Model -&gt; ( Model, Cmd Msg )
update msg model =
  case msg of
    NoOp -&gt;
      model ! []        &lt;-- What is this?
</code></pre>

<p>What I (think I) understand, is that the <code>update</code> function takes in a <code>msg</code> of type <code>Msg</code> and a <code>model</code> of type <code>Model</code>, and returns a tuple of containing a <code>Model</code> and a <code>Cmd Msg</code>.</p>

<p>But how should I read the return statement?</p>

<pre><code>model ! []
</code></pre>

<p>What does this statement mean? return a "model [something] empty list"?<br>
Did I miss something in the docs where this is explained? (Googling "elm !" did not get me far :)</p>
