code.rkt

#lang plait

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;;; starter code: do not modify
(define-type IfLang
  (boolE [b : Boolean])
  (ifE [g : IfLang] [thn : IfLang] [els : IfLang])
  (tryE [e : IfLang] [handle-id : Symbol] [handler : IfLang])
  (raiseE [id : Symbol]))

(define-type Frame
  (handleF [id : Symbol] [h : IfLang])
  (ifF [thn : IfLang] [els : IfLang]))


(define-type State
  (state [C : IfLang]
         [K : (Listof Frame)]))

;;; push f onto the frame stack
(define (push-frame f stack)
  (append (list f) stack))

(define (pop-frame stack)
  (type-case (Listof Frame) stack
             [(cons hd tl)
              (pair hd tl)]
             [empty (error 'invalid "popping empty stack frame")]))

;;; runs the machine beginning from `state` until a fixed point is reached
(define (run-machine s)
  (begin
    ; uncomment these lines to see the state of your machine progress
    ; (display s)
    ; (display "\n")
    (let [(next-state (transition s))]
      (if (equal? next-state s)
          s
          (run-machine next-state)))))

;;; run the machine starting in control register e with
;;; store size store-size
(run-machine-init : (IfLang -> IfLang))
(define (run-machine-init e)
  (let [(r (run-machine (state e empty)))]
    (state-C r)))

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;;; problem 1
;;; your solution goes here
(transition : (State -> State))
(define (transition s)
  (error 'implementme ""))