title: Lua unusual variable name (question mark variable)
body: <p>I have stumbled upon this line of code and I am not sure what the <code>[ ? ]</code> part represents (my guess is it's a sort of a wildcard but I searched it for a while and couldn't find anything):</p>
  <pre><code>['?'] = function() return is_canadian and &quot;eh&quot; or &quot;&quot; end
  </code></pre>
  <p>I understand that RHS is a functional ternary operator. I am curious about the LHS and what it actually is.</p>
  <p>Edit: reference (2nd example):</p>
  <p><a href="http://lua-users.org/wiki/SwitchStatement" rel="nofollow noreferrer">http://lua-users.org/wiki/SwitchStatement</a></p>