diff options
Diffstat (limited to 'stlc-ref.rkt')
| -rw-r--r-- | stlc-ref.rkt | 60 |
1 files changed, 30 insertions, 30 deletions
diff --git a/stlc-ref.rkt b/stlc-ref.rkt index b025309..f054d4e 100644 --- a/stlc-ref.rkt +++ b/stlc-ref.rkt @@ -4,9 +4,9 @@ ;; The Simply-Typed Lambda Calculus with references ;; (interpret Expr Table[Sym, Expr] Table[Sym, Expr]): Value -(define (interpret expr [Γ #hash()] [Σ (make-hash)]) - (interpret- (strip (desugar expr)) Γ Σ)) -(define (interpret- expr Γ Σ) +(define (interpret expr) + (interpret-core (strip (desugar expr)) #hash() (make-hash))) +(define (interpret-core expr Γ Σ) ; (print (format "interpret: ~a" (fmt expr))) (match expr ['sole 'sole] @@ -18,30 +18,30 @@ (let ([r (gensym)]) (dict-set! Σ r e) r)] [`(! ,e) - (let ([r (interpret- e Γ Σ)]) + (let ([r (interpret-core e Γ Σ)]) (if (dict-has-key? Σ r) - (interpret- (dict-ref Σ r) Γ Σ) + (interpret-core (dict-ref Σ r) Γ Σ) (err (format "attempting to deref unknown reference ~a" r))))] [`(set ,e1 ,e2) - (let ([r (interpret- e1 Γ Σ)]) - (if (dict-has-key? Σ r) (dict-set! Σ r (interpret- e2 Γ Σ)) + (let ([r (interpret-core e1 Γ Σ)]) + (if (dict-has-key? Σ r) (dict-set! Σ r (interpret-core e2 Γ Σ)) (err (format "attempting to update unknown reference ~a" r)))) 'sole] [`(λ ,x ,e) `(λ ,x ,e ,Γ)] [`(λ ,x ,e ,env) `(λ ,x ,e ,env)] ; ??? [`(,e1 ,e2) - (match (interpret- e1 Γ Σ) + (match (interpret-core e1 Γ Σ) [`(λ ,x ,e1 ,env) - (interpret- e1 (dict-set env x (interpret- e2 Γ Σ)) Σ)] + (interpret-core e1 (dict-set env x (interpret-core e2 Γ Σ)) Σ)] [e1 (err (format "attempting to interpret arg ~a applied to unknown expression ~a" e2 e1))])] [e (err (format "attempting to interpret unknown expression ~a" e))])) ;; (check Expr Type Table[Sym, Type]): Bool -(define (check expr with [Γ #hash()]) - (check- (desugar expr) with Γ)) -(define (check- expr with Γ) +(define (check expr with) + (check-core (desugar expr) with #hash())) +(define (check-core expr with Γ) ; (print (format "check: ~a" (fmt expr))) (match* (expr with) [('sole 'Unit) #t] @@ -49,27 +49,27 @@ [(x _) #:when (dict-has-key? Γ x) (equal? (dict-ref Γ x) with)] - [(`(new ,e) `(Ref ,t)) (check- e t Γ)] - [(`(! ,e) t) (check- e `(Ref ,t) Γ)] + [(`(new ,e) `(Ref ,t)) (check-core e t Γ)] + [(`(! ,e) t) (check-core e `(Ref ,t) Γ)] [(`(set ,e1 ,e2) 'Unit) - (match (infer- e1 Γ) - [`(Ref ,t) (check- e2 t Γ)] + (match (infer-core e1 Γ) + [`(Ref ,t) (check-core e2 t Γ)] [t #f])] [(`(λ (,x : ,t) ,e) `(,t1 → ,t2)) - (and (equal? t t1) (check- e t2 (dict-set Γ x t1)))] + (and (equal? t t1) (check-core e t2 (dict-set Γ x t1)))] [(`(,e1 ,e2) t) - (match (infer- e1 Γ) + (match (infer-core e1 Γ) [`(,t1 → ,t2) - (and (equal? t2 t) (equal? t1 (infer- e2 Γ)))] + (and (equal? t2 t) (equal? t1 (infer-core e2 Γ)))] [t #f])] [(e t) #f])) ;; (infer Expr Table[Sym, Type]): Type -(define (infer expr [Γ #hash()]) - (infer- (desugar expr) Γ)) -(define (infer- expr Γ) +(define (infer expr) + (infer-core (desugar expr) #hash())) +(define (infer-core expr Γ) ; (print (format "infer: ~a" (fmt expr))) (match expr ['sole 'Unit] @@ -77,25 +77,25 @@ [x #:when (dict-has-key? Γ x) (dict-ref Γ x)] - [`(new ,e) `(Ref ,(infer- e Γ))] + [`(new ,e) `(Ref ,(infer-core e Γ))] [`(! ,e) - (match (infer- e Γ) + (match (infer-core e Γ) [`(Ref ,t) t] [t (err "attempting to deref term not of Ref type!")])] [`(set ,e1 ,e2) - (match (infer- e1 Γ) + (match (infer-core e1 Γ) [`(Ref ,t) - (if (check- e2 t Γ) 'Unit + (if (check-core e2 t Γ) 'Unit (err (format "attempting to update ~a: ~a with term ~a: ~a of differing type" - e1 t e2 (infer- e2 Γ))))] + e1 t e2 (infer-core e2 Γ))))] [t (err (format "attempting to update non-reference ~a: ~a" e1 t))])] [`(λ (,x : ,t) ,e) - `(,t → ,(infer- e (dict-set Γ x t)))] + `(,t → ,(infer-core e (dict-set Γ x t)))] [`(,e1 ,e2) - (match (infer- e1 Γ) + (match (infer-core e1 Γ) [`(,t1 → ,t2) - (if (check- e2 t1 Γ) t2 + (if (check-core e2 t1 Γ) t2 (err (format "inferred argument type ~a does not match arg ~a" t1 e2)))] [t (err (format "expected → type on application body, got ~a" t))])] |