Task

Create a stack-based evaluator for an expression in   reverse Polish notation (RPN)   that also shows the changes in the stack as each individual token is processed as a table.



 Assume an input of a correct, space separated, string of tokens of an RPN expression
 Test with the RPN expression generated from the   Parsing/Shunting-yard algorithm   task: 

         3 4 2 * 1 5 - 2 3 ^ ^ / + 

 Print or display the output here


Notes

    ^    means exponentiation in the expression above.
    /    means division.


See also

   Parsing/Shunting-yard algorithm for a method of generating an RPN from an infix expression.
   Several solutions to 24 game/Solve make use of RPN evaluators (although tracing how they work is not a part of that task).
   Parsing/RPN to infix conversion.
   Arithmetic evaluation.


(de rpnCalculator (Str)
   (let (^ **  Stack)  # Define '^' from the built-in '**'
      (prinl "Token  Stack")
      (for Token (str Str "*+-/\^")
         (if (num? Token)
            (push 'Stack @)
            (set (cdr Stack)
               ((intern Token) (cadr Stack) (pop 'Stack)) ) )
         (prin Token)
         (space 6)
         (println Stack) )
      (println (car Stack)) ) )