title: Default value in clojure maps
body: <p>I have a clojure map. Name it <code>opts</code>. I know 2 ways to get values from this map such that if there is no key get some default value:</p>
  
  <pre><code>(let [opts {}
        title-1 (or (:title opts) "Default title")
        title-2 (:title opts "Default title")]
    (println title-1 title-2))
  </code></pre>
  
  <p>I saw some libraries (quil, incanter) use first approach with <code>or</code>. It seems to me that second approach is more concise and cleaner. Is there advantages in the first approach?<br>
  Disadvantage of using <code>(or (:title opts) "Default value")</code> is that we cannot pass <code>false</code> and <code>nil</code> as values anymore, default value is always used in this case.</p>