title: Add Function Within Variable String
body: <p>I am trying to add a function within string to show the output of function via shortcode but it is showing error. </p>
  
  <pre><code>function foo_shortcode($atts, $content = null) { 
  
  $datashortcode = '&lt;div&gt;'
  
  .if(function_exists('rtb_kk'))
  {
      rtb_kk();
  }. 
  '&lt;/div&gt;'
  ;
  
  return $datashortcode; 
  }
  
  add_shortcode('showfoo', 'foo_shortcode');
  </code></pre>
  
  <p>Where i am making mistake? </p>