title: Jade radio button checked condition
body: <p>I have form in Jade file, and I want it to be pre-filled with some values that come from backend.In the form, there are radio buttons for user gender.</p>
  
  <pre><code>input(type="radio", name="gender_filter", value="1") Male
  input(type="radio", name="gender_filter", value="0") Female
  </code></pre>
  
  <p>Now I also have this variable <code>gender_param</code>, and I want the corresponding button to be selected when page loads.
  In <strong>PHP</strong>, I could do this:</p>
  
  <pre><code>&lt;input type="radio" name="gender_filter", value="1" &lt;?php echo ($gender_param==1)?"checked":''; ?&gt;&gt;
  </code></pre>
  
  <p>Is there the corresponding syntax for Jade? Or I need to write it in the long way with line duplicates like</p>
  
  <pre><code>- if gender_param==1
     input(type="radio", name="gender_filter", value="1", checked) Male
  - else
     input(type="radio", name="gender_filter", value="1") Male
  </code></pre>