title: What does the `<<` operator mean in elm?
body: <p>In the following code taken from <a href="http://elm-lang.org/edit/examples/Intermediate/Form.elm" rel="noreferrer">Elm Form Example</a>, line 122, what does the <code>&lt;&lt;</code> operator mean?</p>
  
  <pre><code>Field.field Field.defaultStyle (Signal.send updateChan &lt;&lt; toUpdate) "" content
  </code></pre>
  
  <p>Couldn't find it in <a href="http://elm-lang.org/learn/Syntax.elm" rel="noreferrer">Elm syntax reference</a>.</p>
  
  <p>Does it mean, when the field changes, instead of sending its <code>content</code> to <code>updateChan</code>, send <code>toUpdate</code> to <code>updateChan</code>?</p>