title: What exactly is a Phoenix "Layout"?
body: <p>In the Elixir IRC, <code>josevalim</code> <a href="http://irc.programmingelixir.com/search/date?date=2014-12-31#1420019758" rel="noreferrer">refers to a way to compose templates in Phoenix</a>, by defining and then using a layout helper, as such:</p>
  
  <pre><code>&lt;%= with_layout Layout, "app..." do %&gt;hello&lt;% end %&gt;
  </code></pre>
  
  <p>I'm very new to Phoenix, but I'm assuming the <code>with_layout</code> helper is defined in the view corresponding to the template above, but I can't figure out where/how to define and/or access this <code>Layout</code>.  I'm familiar now with "templates" and "views", but can't find much info on Phoenix layouts or layout helpers.</p>
  
  <p>So my question is, what exactly does <code>Layout</code> refer to here, and how do Phoenix "layouts" differ from "templates"?</p>