title: Use JSON.parse to parse OpenStruct or a hash
body: <p>I tried to parse a simple JSON like that:</p>
  
  <pre><code>JSON.parse({"pong": "ok"})
  </code></pre>
  
  <p>and it failed</p>
  
  <pre><code>2.4.0 :014 &gt; JSON.parse({"pong": "ok"})
  TypeError: no implicit conversion of Hash into String
      from (irb):14
  </code></pre>
  
  <p>What's wrong here ? Why should I convert to String ? </p>
  
  <p>Another try, with <strong>OpenStruct</strong> this time:</p>
  
  <pre><code>2.4.0 :001 &gt; pong = OpenStruct.new(pong: 'OK')
   =&gt; #&lt;OpenStruct pong="OK"&gt; 
  2.4.0 :002 &gt; JSON.parse(pong)
  TypeError: no implicit conversion of OpenStruct into String
      from (irb):2
  </code></pre>
  
  <p>The same ?
  Thank you</p>