#lang typed/racket
(require "ast.rkt")

(struct State ([stack : Stack] [dump : Dump] [heap : Heap] [globals : Globals] [stats : Stats]))
(define-type Addr Symbol)
(define-type Stack (Listof Addr))
(define-type Dump Null)
(define-type Heap (Immutable-HashTable Addr Node))
(define-type Node (∪ (List Addr Addr) CoreScDefn Integer))
(define-type Globals (Immutable-HashTable Name Addr))
(define-type Stats Nonnegative-Integer)

(: new-addr (-> Addr))
(define (new-addr)
  (gensym))

(: initial-dump Dump)
(define initial-dump '())

(: initial-stats Stats)
(define initial-stats 0)

(: incr-stats (-> Stats Stats))
(define incr-stats add1)

(: update-stats (-> (-> Stats Stats) State State))
(define (update-stats f mstate)
  (struct-copy State mstate [stats (f (State-stats mstate))]))

(: allocate-node (-> Heap Node (Values Heap Addr)))
(define (allocate-node heap node)
  (let ([addr (new-addr)])
    (values (hash-set heap addr node) addr)))

(: allocate-sc (-> Heap CoreScDefn (Values Heap (Pair Name Addr))))
(define (allocate-sc heap scdef)
  (let-values ([(heap addr) (allocate-node heap scdef)])
    (values heap (cons (scdefn-name scdef) addr))))


;; (: initial-heap (-> (Listof CoreScDefn) (Values Heap Globals)))
;; (define (initial-heap scs)
;;   (for/fold ([heap ])))