title: How to get fields of a Julia object
body: <p>Given a Julia object of composite type, how can one determine its fields?</p>
  
  <p>I know one solution if you're working in the REPL: First you figure out the type of the object via a call to <code>typeof</code>, then enter help mode (<code>?</code>), and then look up the type.  Is there a more programmatic way to achieve the same thing?</p>