title: Postfix notation to expression tree
body: <p>There are enough resources on how to convert an expression tree into postfix notation, and it's not that hard.</p>
  
  <p>But I have to parse a postfix expression into an expression tree.</p>
  
  <p>The expression is:</p>
  
  <blockquote>
    <p>A 2 ^ 2 A * B * - B 2 ^ + A B - /</p>
  </blockquote>
  
  <p>I don't really have a clue on how to interpret the expression. Does someone has a clue on how to proces this?</p>