title: What is val it in sml?
body: <p>I have an example looks like this.</p>
  
  <pre><code>type int_pair = int * int;
  
  val it:int_pair = (1,1);
  </code></pre>
  
  <p>I don't quite understand what does val it means and in what condition we will use val.</p>
  
  <p>Does it mean we are assigning value to the int_pair it?</p>