diff options
Diffstat (limited to 'semestr-2/racket/lista6/lista8/zad6.bak')
| -rw-r--r-- | semestr-2/racket/lista6/lista8/zad6.bak | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/semestr-2/racket/lista6/lista8/zad6.bak b/semestr-2/racket/lista6/lista8/zad6.bak new file mode 100644 index 0000000..721f5bf --- /dev/null +++ b/semestr-2/racket/lista6/lista8/zad6.bak @@ -0,0 +1,151 @@ +#lang racket + +; Do list.rkt dodajemy procedury +; +; Miejsca, ktore sie zmienily oznaczone sa przez !!! + +; --------- ; +; Wyrazenia ; +; --------- ; + +(struct const (val) #:transparent) +(struct binop (op l r) #:transparent) +(struct unop (op e) #:transparent) +(struct var-expr (id) #:transparent) +(struct let-expr (id e1 e2) #:transparent) +(struct if-expr (eb et ef) #:transparent) +(struct cons-expr (e1 e2) #:transparent) +(struct null-expr () #:transparent) +(struct null?-expr (e) #:transparent) +(struct app (f e) #:transparent) ; <------------------ !!! +(struct lam (id e) #:transparent) ; <------------------ !!! + + +(define (expr? e) + (match e + [(const n) (or (number? n) (boolean? n))] + [(binop op l r) (and (symbol? op) (expr? l) (expr? r))] + [(var-expr x) (symbol? x)] + [(let-expr x e1 e2) + (and (symbol? x) (expr? e1) (expr? e2))] + [(if-expr eb et ef) + (and (expr? eb) (expr? et) (expr? ef))] + [(cons-expr e1 e2) (and (expr? e1) (expr? e2))] + [(null-expr) true] + [(null?-expr e) (expr? e)] + [(app f e) (and (expr? f) (expr? e))] ; <--------------------- !!! + [(lam id e) (and (symbol? id) (expr? e))] ; <----------------- !!! + [_ false])) + +(define (parse q) + (cond + [(number? q) (const q)] + [(eq? q 'true) (const true)] + [(eq? q 'false) (const false)] + [(eq? q 'null) (null-expr)] + [(symbol? q) (var-expr q)] + [(and (list? q) (eq? (length q) 2) (eq? (first q) 'null?)) + (null?-expr (parse (second q)))] + [(and (list? q) (eq? (length q) 3) (eq? (first q) 'cons)) + (cons-expr (parse (second q)) + (parse (third q)))] + [(and (list? q) (eq? (length q) 3) (eq? (first q) 'let)) + (let-expr (first (second q)) + (parse (second (second q))) + (parse (third q)))] + [(and (list? q) (eq? (length q) 4) (eq? (first q) 'if)) + (if-expr (parse (second q)) + (parse (third q)) + (parse (fourth q)))] + [(and (list? q) (eq? (length q) 3) (eq? (first q) 'lambda)) ; <!!! + (parse-lam (second q) (third q))] + [(and (list? q) (pair? q) (not (op->proc (car q)))) ; <------- !!! + (parse-app q)] + [(and (list? q) (eq? (length q) 3) (symbol? (first q))) + (binop (first q) + (parse (second q)) + (parse (third q)))] + [(and (list? q) (eq? (length q) 2) (symbol? (first q))) + (unop (first q) (parse (second q)))])) + +(define (parse-app q) ; <----------------------------------------- !!! + (define (parse-app-accum q acc) + (cond [(= 1 (length q)) (app acc (parse (car q)))] + [else (parse-app-accum (cdr q) (app acc (parse (car q))))])) + (parse-app-accum (cdr q) (parse (car q)))) + +(define (parse-lam pat e) ; <------------------------------------- !!! + (cond [(= 1 (length pat)) + (lam (car pat) (parse e))] + [else + (lam (car pat) (parse-lam (cdr pat) e))])) + +; ---------- ; +; Srodowiska ; +; ---------- ; + +(struct environ (xs) #:transparent) + +(define env-empty (environ null)) +(define (env-add x v env) + (environ (cons (cons x v) (environ-xs env)))) +(define (env-lookup x env) + (define (assoc-lookup xs) + (cond [(null? xs) (error "Unknown identifier" x)] + [(eq? x (car (car xs))) (cdr (car xs))] + [else (assoc-lookup (cdr xs))])) + (assoc-lookup (environ-xs env))) + +; --------- ; +; Ewaluacja ; +; --------- ; + +(struct clo (id e env) #:transparent) ; <------------------------- !!! + +(define (value? v) + (or (number? v) + (boolean? v) + (and (pair? v) (value? (car v)) (value? (cdr v))) + (null? v) + (clo? v))) ; <---------------------------------------------- !!! + +(define (op->proc op) + (match op ['+ +] ['- -] ['* *] ['/ /] ['% modulo] + ['= =] ['> >] ['>= >=] ['< <] ['<= <=] + ['and (lambda (x y) (and x y))] + ['or (lambda (x y) (or x y))] + ['not not] ['car car] ['cdr cdr] + [_ false])) ; <--------------------------------------- !!! + +(define (eval-env e env) + (match e + [(const n) n] + [(binop op l r) ((op->proc op) (eval-env l env) + (eval-env r env))] + [(unop op e) ((op->proc op) (eval-env e env))] + [(let-expr x e1 e2) + (eval-env e2 (env-add x (eval-env e1 env) env))] + [(var-expr x) (env-lookup x env)] + [(if-expr eb et ef) (if (eval-env eb env) + (eval-env et env) + (eval-env ef env))] + [(cons-expr e1 e2) (cons (eval-env e1 env) + (eval-env e2 env))] + [(null-expr) null] + [(null?-expr e) (null? (eval-env e env))] + [(lam x e) (clo x e env)] ; <--------------------------------- !!! + [(app f e) ; <------------------------------------------------ !!! + (let ([vf (eval-env f env)] + [ve (eval-env e env)]) + (match vf [(clo x body fun-env) + (eval-env body (env-add x ve fun-env))]))])) + +(define (eval e) (eval-env e env-empty)) + +(define program + '(let [twice (lambda (f x) (f (f x)))] + (let [inc (lambda (x) (+ 1 x))] + (twice twice twice twice inc 1)))) + + +(define (test-eval) (eval (parse program)))
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