title: How to XOR hexadecimal in SML?
body: <p>I would like to implement a XOR(exclusive or) function into SML that is able to XOR hexadecimals.
  Do I need to calculate the binary of the HEX and XOR then? And if yes, how do I do this/how do I reverse this so I get HEX as result?
  An example :</p>
  
  <p>xorhex (0wx4A, 0wx6F)</p>
  
  <blockquote>
    <p>val it = 0wx25 : word8</p>
  </blockquote>
  
  <p>How can I implement this in preferably MoscowML?<br>
  Thanks in advance </p>