title: User-defined types of specific values in Haskell?
body: <p>I have googled the heck out of this, but haven't been able to find anything relevant (surprises me, since it would seem to be an obvious thing many would want to try).</p>
  
  <p>I want to do something like this:</p>
  
  <pre><code>data Car = "ford" | "chevy"
  </code></pre>
  
  <p>In other words, I want the values on the right hand side to be specific values, i.e. particular strings, particular numbers, etc. rather than something general.</p>
  
  <p>Is this possible?  How do I do it?</p>
  
  <p>Thanks.</p>
  
  <p>EDIT:  I am not looking for: data Car = Ford | Chevy</p>