(  ( show
  =   line a
    .   \n:?line
      &   whl
        ' (!arg:%?a ?arg&!a " " !line:?line)
      & put$(str$!line)
  )
& :?stack
&   map
  $ ( (
      =   a b
        .   show$(!arg !stack)
          &     (     !arg
                    : ( "+"
                      | "-"
                      | "*"
                      | "/"
                      | "^"
                      )
                  & !stack:%?a %?b ?stack
                  & ( !arg:"+"&!a+!b
                    | !arg:"-"&-1*!a+!b
                    | !arg:"*"&!a*!b
                    | !arg:"/"&!a*!b^-1
                    | !a^!b
                    )
                | !arg
                )
                !stack
            : ?stack
      )
    . vap$((=.!arg).get'(,STR)." ")
    )
& out$!stack
)