[ stack ]                                 is switch.arg (     --> [ )

[ switch.arg put ]                        is switch     (   x -->   )

[ switch.arg release ]                    is otherwise  (     -->   )

[ switch.arg share
  != iff ]else[ done
  otherwise
  ]'[ do ]done[ ]                         is case       (   x -->   )

[ say "Applying: "
  swap echo$ sp
  temp take
  temp take
  swap rot do
  temp put ]                              is apply      ( $ x -->   )

[ say "Pushing:  " dup echo$ sp
  $->n drop temp put ]                    is isnumber   (   $ -->   )

[ temp copy echo cr ]                     is display    (     -->   )

[ nest$ witheach
    [ dup switch
      [ $ '+' case [ ' +  apply ]
        $ '-' case [ ' -  apply ]
        $ '*' case [ ' *  apply ]
        $ '/' case [ ' /  apply ]
        $ '^' case [ ' ** apply ]
        otherwise  [ isnumber ] ]
      display ]
  temp take ]                             is rpncalc    (   $ --> n )

$ "3 4 2 * 1 5 - 2 3 ^ ^ / +" rpncalc
say "Result: " echo