title: Check whether an input is real of integer
body: <p>I want to ask the user to input a variable and check it is real or integer and take two different operations for corresponding actions. Say true if integer else false;</p>
  
  <p>fun realorinteger(n)= if n=int then true else false;</p>
  
  <p>but it definitely does not work. I tried if n in int as well.</p>
  
  <p>Any help?</p>