title: How to combine case statement patterns
body: <p>I'm trying to match on many different constructors in a case statement. For simplicity, assume in half the cases we do the same thing, and in the other half we do something else. Even if I factor out the logic to another function, I still have to write:</p>
  
  <pre><code>case x of
    C1 -&gt; foo x
    C2 -&gt; foo x
    ...
    C10 -&gt; bar x
    C11 -&gt; bar x
    ...
  </code></pre>
  
  <p>Is there some way to make case statements behave more like <code>switch</code> statements in C (i.e. with fallthrough), or so that I can match on one of many patterns at once, like:</p>
  
  <pre><code>case x of
    C1, C2, C3 -&gt; foo x
    C10, C11, C12 -&gt; bar x
  </code></pre>
  
  <p>Or perhaps another way to clean this up?</p>