title: print and return another value in Clojure
body: <p>I have a Clojure beginner question about why the following code doesn't work :</p>
  
  <pre><code>(defn aFun [n]
    (if (&lt; -10 n 10) 
         ((println "Single digit" n) "A return value")
         ((println "More digits" n) "Another return value")))
  </code></pre>
  
  <p>I get a <code>NullPointerException</code> at runtime. Why ?</p>
  
  <p>This function works :</p>
  
  <pre><code>(defn aFun [n]
    (if (&lt; -10 n 10) 
         "A return value"
         "Another return value"))
  </code></pre>
  
  <p>And this one too :</p>
  
  <pre><code>(defn aFun [n]
    (if (&lt; -10 n 10) 
         (println "Single digit" n)
         (println "More digits" n)))
  </code></pre>
  
  <p>I'd like to do both at the same time however : (compute and) return a value, while printing some things first. I'm sure this is pretty basic (not even sure how to title my question), but I can't get what I am doing wrong.</p>