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.


[Float] a
[String = ((Float, Float) -> Float)] b
b[‘+’] = (x, y) -> y + x
b[‘-’] = (x, y) -> y - x
b[‘*’] = (x, y) -> y * x
b[‘/’] = (x, y) -> y / x
b[‘^’] = (x, y) -> y ^ x
 
L(c) ‘3 4 2 * 1 5 - 2 3 ^ ^ / +’.split(‘ ’)
   I c C b
      V first  = a.pop()
      V second = a.pop()
      a.append(b[c](first, second))
   E
      a.append(Float(c))
   print(c‘ ’a)