title: Call function without assigning returning value based on syntax diagram
body: <p>From <a href="http://primepuzzle.com/tp2/syntax-diagrams.html" rel="nofollow noreferrer">Peter Grogono's "Programming in PASCAL" Addison Wesley 1980</a>, a statement is defined as:</p>
  
  <p><a href="https://i.stack.imgur.com/2sGvh.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2sGvh.jpg" alt="enter image description here"></a>
  <a href="https://i.stack.imgur.com/myrOs.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/myrOs.jpg" alt="enter image description here"></a></p>
  
  <p>In this diagram, I don't see how I can call the function as a statement; the only way to call it is to make a new temporary variable, then assign it with the desired function as an expression.</p>
  
  <p>How can I call function without assigning the returning value?</p>