14 files changed, 1213 insertions, 0 deletions
diff --git a/semestr-2/racket/lista6/lista8/kappa.py b/semestr-2/racket/lista6/lista8/kappa.py
new file mode 100644
index 0000000..f359d5c
--- /dev/null
+++ b/semestr-2/racket/lista6/lista8/kappa.py
@@ -0,0 +1,13 @@
+import pylab 
+
+a = int(input("podaj liczbe: "))
+b = int(input("podaj liczbe: "))
+
+x = range(-10, 11) 
+y = [] 
+for i in x: 
+    y.append(a * i + b) 
+pylab.plot(x, y) 
+pylab.title('Wykres f(x) = a*x - b') 
+pylab.grid(True) 
+pylab.show()
diff --git a/semestr-2/racket/lista6/lista8/zad1.bak b/semestr-2/racket/lista6/lista8/zad1.bak
new file mode 100644
index 0000000..0960f21
--- /dev/null
+++ b/semestr-2/racket/lista6/lista8/zad1.bak
@@ -0,0 +1,98 @@
+#lang racket
+
+; Do let-env.rkt dodajemy wartosci boolowskie
+;
+; Miejsca, ktore sie zmienily oznaczone sa przez !!!
+
+; --------- ;
+; Wyrazenia ;
+; --------- ;
+
+(struct const    (val)      #:transparent)
+(struct binop    (op l r)   #:transparent)
+(struct var-expr (id)       #:transparent)
+(struct let-expr (id e1 e2) #:transparent)
+(struct if-expr  (eb et ef) #: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))]
+    [_ false]))
+
+(define (parse q)
+  (cond
+    [(number? q) (const q)]
+    [(eq? q 'true)  (const true)]  ; <---------------------------- !!!
+    [(eq? q 'false) (const false)] ; <---------------------------- !!!
+    [(symbol? q) (var-expr 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) (symbol? (first q)))
+     (binop (first q)
+            (parse (second q))
+            (parse (third q)))]))
+
+(define (test-parse) (parse '(let [x (+ 2 2)] (+ x 1))))
+
+; ---------- ;
+; Srodowiska ;
+; ---------- ;
+
+(struct environ (xs))
+
+(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 ;
+; --------- ;
+
+(define (value? v)
+  (or (number? v) (boolean? v)))
+
+(define (op->proc op)
+  (match op ['+ +] ['- -] ['* *] ['/ /] ['% modulo] ; <----------- !!!
+            ['= =] ['> >] ['>= >=] ['< <] ['<= <=]
+            ['and (lambda (x y) (and x y))]
+            ['or  (lambda (x y) (or  x y))]))
+
+(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))]
+    [(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))]))
+
+(define (eval e) (eval-env e env-empty))
+
+(define program
+  '(if (or (< (% 123 10) 5)
+           true)
+       (+ 2 3)
+       (/ 2 0)))
+
+(define (test-eval) (eval (parse program)))
+\ No newline at end of file
diff --git a/semestr-2/racket/lista6/lista8/zad1.rkt b/semestr-2/racket/lista6/lista8/zad1.rkt
new file mode 100644
index 0000000..1cd6b0b
--- /dev/null
+++ b/semestr-2/racket/lista6/lista8/zad1.rkt
@@ -0,0 +1,104 @@
+#lang racket
+
+; Do let-env.rkt dodajemy wartosci boolowskie
+;
+; Miejsca, ktore sie zmienily oznaczone sa przez !!!
+
+; --------- ;
+; Wyrazenia ;
+; --------- ;
+
+(struct const        (val)        #:transparent)
+(struct binop        (op l r)     #:transparent)
+(struct var-expr     (id)         #:transparent)
+(struct let-expr     (id e1 e2)   #:transparent)
+(struct if-expr      (eb et ef)   #: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))]
+    [_ false]))
+
+(define (parse q)
+  (cond
+    [(number? q) (const q)]
+    [(eq? q 'true)  (const true)]  ; <---------------------------- !!!
+    [(eq? q 'false) (const false)] ; <---------------------------- !!!
+    [(symbol? q) (var-expr 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) 'and))
+     (if-expr (parse (second q))
+              (parse (third q))
+              (const false))]
+    [(and (list? q) (eq? (length q) 3) (eq? (first q) 'or))
+     (if-expr (parse (second q))
+              (const true)
+              (parse (third q)))]
+    [(and (list? q) (eq? (length q) 3) (symbol? (first q)))
+     (binop (first q)
+            (parse (second q))
+            (parse (third q)))]))
+
+(define (test-parse) (parse '(let [x (+ 2 2)] (+ x 1))))
+
+; ---------- ;
+; Srodowiska ;
+; ---------- ;
+
+(struct environ (xs))
+
+(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 ;
+; --------- ;
+
+(define (value? v)
+  (or (number? v) (boolean? v)))
+
+(define (op->proc op)
+  (match op ['+ +] ['- -] ['* *] ['/ /] ['% modulo] ; <----------- !!!
+            ['= =] ['> >] ['>= >=] ['< <] ['<= <=]))
+
+(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))]
+    [(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))]))
+
+(define (eval e) (eval-env e env-empty))
+
+(define program
+  '(if (or (< (% 123 10) 5)
+           true)
+       (+ 2 3)
+       (/ 2 0)))
+
+(define (test-eval) (eval (parse program)))
+\ No newline at end of file
diff --git a/semestr-2/racket/lista6/lista8/zad4.bak b/semestr-2/racket/lista6/lista8/zad4.bak
new file mode 100644
index 0000000..503099d
--- /dev/null
+++ b/semestr-2/racket/lista6/lista8/zad4.bak
@@ -0,0 +1,114 @@
+#lang racket
+
+; Do boolean.rkt dodajemy pary
+;
+; Miejsca, ktore sie zmienily oznaczone sa przez !!!
+
+; --------- ;
+; Wyrazenia ;
+; --------- ;
+
+(struct const     (val)      #:transparent)
+(struct binop     (op l r)   #: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 car-expr  (e)        #:transparent) ; <------------------- !!!
+(struct cdr-expr  (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))] ; <----------- !!!
+    [(car-expr e) (expr? e)] ; <---------------------------------- !!!
+    [(cdr-expr e) (expr? e)] ; <---------------------------------- !!!
+    [_ false]))
+
+(define (parse q)
+  (cond
+    [(number? q) (const q)]
+    [(eq? q 'true)  (const true)]
+    [(eq? q 'false) (const false)]
+    [(symbol? q) (var-expr 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) 2) (eq? (first q) 'car)) ; <-- !!!
+     (car-expr (parse (second q)))]
+    [(and (list? q) (eq? (length q) 2) (eq? (first q) 'cdr)) ; <-- !!!
+     (cdr-expr (parse (second 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) (symbol? (first q)))
+     (binop (first q)
+            (parse (second q))
+            (parse (third q)))]))
+
+(define (test-parse) (parse '(let [x (+ 2 2)] (+ x 1))))
+
+; ---------- ;
+; Srodowiska ;
+; ---------- ;
+
+(struct environ (xs))
+
+(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 ;
+; --------- ;
+
+(define (value? v)
+  (or (number? v)
+      (boolean? v)
+      (and (pair? v) (value? (car v)) (value? (cdr v)))))
+
+(define (op->proc op)
+  (match op ['+ +] ['- -] ['* *] ['/ /] ['% modulo]
+            ['= =] ['> >] ['>= >=] ['< <] ['<= <=]
+            ['and (lambda (x y) (and x y))]
+            ['or  (lambda (x y) (or  x y))]))
+
+(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))]
+    [(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))]
+    [(car-expr e) (car (eval-env e env))] ; <--------------------- !!!
+    [(cdr-expr e) (cdr (eval-env e env))])) ; <------------------- !!!
+
+(define (eval e) (eval-env e env-empty))
+
+(define program
+  '(car (if true (cons 1 2) false)))
+
+(define (test-eval) (eval (parse program)))
+\ No newline at end of file
diff --git a/semestr-2/racket/lista6/lista8/zad4.rkt b/semestr-2/racket/lista6/lista8/zad4.rkt
new file mode 100644
index 0000000..7934435
--- /dev/null
+++ b/semestr-2/racket/lista6/lista8/zad4.rkt
@@ -0,0 +1,118 @@
+#lang racket
+
+; Do boolean.rkt dodajemy pary
+;
+; Miejsca, ktore sie zmienily oznaczone sa przez !!!
+
+; --------- ;
+; Wyrazenia ;
+; --------- ;
+
+(struct const     (val)      #:transparent)
+(struct binop     (op l r)   #: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 car-expr  (e)        #:transparent) ; <------------------- !!!
+(struct cdr-expr  (e)        #:transparent) ; <------------------- !!!
+(struct is-pair   (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))] ; <----------- !!!
+    [(car-expr e) (expr? e)] ; <---------------------------------- !!!
+    [(cdr-expr e) (expr? e)] ; <---------------------------------- !!!
+    [(is-pair e)  (expr? e)]
+    [_ false]))
+
+(define (parse q)
+  (cond
+    [(number? q) (const q)]
+    [(eq? q 'true)  (const true)]
+    [(eq? q 'false) (const false)]
+    [(symbol? q) (var-expr 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) 2) (eq? (first q) 'car)) ; <-- !!!
+     (car-expr (parse (second q)))]
+    [(and (list? q) (eq? (length q) 2) (eq? (first q) 'cdr)) ; <-- !!!
+     (cdr-expr (parse (second 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) (symbol? (first q)))
+     (binop (first q)
+            (parse (second q))
+            (parse (third q)))]
+    [(and (list? q) (eq? (length q) 2) (eq? (first q) 'pair?))
+     (is-pair (parse (second q)))]))
+
+(define (test-parse) (parse '(let [x (+ 2 2)] (+ x 1))))
+
+; ---------- ;
+; Srodowiska ;
+; ---------- ;
+
+(struct environ (xs))
+
+(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 ;
+; --------- ;
+
+(define (value? v)
+  (or (number? v)
+      (boolean? v)
+      (and (pair? v) (value? (car v)) (value? (cdr v)))))
+
+(define (op->proc op)
+  (match op ['+ +] ['- -] ['* *] ['/ /] ['% modulo]
+            ['= =] ['> >] ['>= >=] ['< <] ['<= <=]
+            ['and (lambda (x y) (and x y))]
+            ['or  (lambda (x y) (or  x y))]))
+
+(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))]
+    [(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))]
+    [(car-expr e) (car (eval-env e env))] ; <--------------------- !!!
+    [(cdr-expr e) (cdr (eval-env e env))] ; <------------------- !!!
+    [(is-pair e) (cons? (eval-env e env))]))
+(define (eval e) (eval-env e env-empty))
+
+(define program
+  '(car (if true (cons 1 2) false)))
+
+(define (test-eval) (eval (parse program)))
+\ No newline at end of file
diff --git a/semestr-2/racket/lista6/lista8/zad5.bak b/semestr-2/racket/lista6/lista8/zad5.bak
new file mode 100644
index 0000000..6f1f7b4
--- /dev/null
+++ b/semestr-2/racket/lista6/lista8/zad5.bak
@@ -0,0 +1 @@
+#lang racket
diff --git a/semestr-2/racket/lista6/lista8/zad5.rkt b/semestr-2/racket/lista6/lista8/zad5.rkt
new file mode 100644
index 0000000..721f5bf
--- /dev/null
+++ b/semestr-2/racket/lista6/lista8/zad5.rkt
@@ -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)))
+\ No newline at end of file
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)))
+\ No newline at end of file
diff --git a/semestr-2/racket/lista6/lista8/zad6.rkt b/semestr-2/racket/lista6/lista8/zad6.rkt
new file mode 100644
index 0000000..c7ea9f0
--- /dev/null
+++ b/semestr-2/racket/lista6/lista8/zad6.rkt
@@ -0,0 +1,171 @@
+#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))]
+    [(unop op e) (and (symbol? op) (expr? e))]
+    [(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 (cedar? f)
+  (let ((letters (string->list (symbol->string f))))
+    (and (> (length letters) 2)
+         (eq? (first letters) #\c)
+         (eq? (first (reverse letters)) #\r)
+         (andmap (lambda (x) (or (eq? x #\a) (eq? x #\d)))
+                 (cdr letters)))))
+
+(define (get-cedar letters xs)
+  (cond [(eq? (car letters) #\r) xs]
+        [(eq? (car letters) #\a) (unop 'car (get-cedar (cdr letters) xs))]
+        [(eq? (car letters) #\d) (unop 'cdr (get-cedar (cdr letters) xs))]))
+
+(define (cedar f xs)
+  (let ((letters (string->list (symbol->string f))))
+    (get-cedar (cdr (reverse letters)) xs)))
+
+(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) (eq? (length q) 2) (symbol? (first q))
+          (cedar? (first q)))
+     (cedar (first q) (parse (second 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)))
+\ No newline at end of file
diff --git a/semestr-2/racket/lista6/lista8/zadanie.rkt b/semestr-2/racket/lista6/lista8/zadanie.rkt
new file mode 100644
index 0000000..0960f21
--- /dev/null
+++ b/semestr-2/racket/lista6/lista8/zadanie.rkt
@@ -0,0 +1,98 @@
+#lang racket
+
+; Do let-env.rkt dodajemy wartosci boolowskie
+;
+; Miejsca, ktore sie zmienily oznaczone sa przez !!!
+
+; --------- ;
+; Wyrazenia ;
+; --------- ;
+
+(struct const    (val)      #:transparent)
+(struct binop    (op l r)   #:transparent)
+(struct var-expr (id)       #:transparent)
+(struct let-expr (id e1 e2) #:transparent)
+(struct if-expr  (eb et ef) #: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))]
+    [_ false]))
+
+(define (parse q)
+  (cond
+    [(number? q) (const q)]
+    [(eq? q 'true)  (const true)]  ; <---------------------------- !!!
+    [(eq? q 'false) (const false)] ; <---------------------------- !!!
+    [(symbol? q) (var-expr 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) (symbol? (first q)))
+     (binop (first q)
+            (parse (second q))
+            (parse (third q)))]))
+
+(define (test-parse) (parse '(let [x (+ 2 2)] (+ x 1))))
+
+; ---------- ;
+; Srodowiska ;
+; ---------- ;
+
+(struct environ (xs))
+
+(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 ;
+; --------- ;
+
+(define (value? v)
+  (or (number? v) (boolean? v)))
+
+(define (op->proc op)
+  (match op ['+ +] ['- -] ['* *] ['/ /] ['% modulo] ; <----------- !!!
+            ['= =] ['> >] ['>= >=] ['< <] ['<= <=]
+            ['and (lambda (x y) (and x y))]
+            ['or  (lambda (x y) (or  x y))]))
+
+(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))]
+    [(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))]))
+
+(define (eval e) (eval-env e env-empty))
+
+(define program
+  '(if (or (< (% 123 10) 5)
+           true)
+       (+ 2 3)
+       (/ 2 0)))
+
+(define (test-eval) (eval (parse program)))
+\ No newline at end of file
diff --git a/semestr-2/racket/lista6/solution.bak b/semestr-2/racket/lista6/solution.bak
new file mode 100644
index 0000000..0805991
--- /dev/null
+++ b/semestr-2/racket/lista6/solution.bak
@@ -0,0 +1,27 @@
+#lang racket
+
+(provide (struct-out complex) parse eval)
+
+(struct complex (re im) #:transparent)
+
+(define value?
+  complex?)
+
+;; Ponizej znajduje sie interpreter zwyklych wyrazen arytmetycznych.
+;; Zadanie to zmodyfikowac go tak, by dzialal z liczbami zespolonymi.
+
+(struct const (val)    #:transparent)
+(struct binop (op l r) #:transparent)
+
+(define (op->proc op)
+  (match op ['+ +] ['- -] ['* *] ['/ /]))
+
+(define (eval e)
+  (match e
+    [(const n) n]
+    [(binop op l r) ((op->proc op) (eval l) (eval r))]))
+
+(define (parse q)
+  (cond [(number? q) (const q)]
+        [(and (list? q) (eq? (length q) 3) (symbol? (first q)))
+         (binop (first q) (parse (second q)) (parse (third q)))]))
+\ No newline at end of file
diff --git a/semestr-2/racket/lista6/solution.rkt b/semestr-2/racket/lista6/solution.rkt
new file mode 100644
index 0000000..59bdecd
--- /dev/null
+++ b/semestr-2/racket/lista6/solution.rkt
@@ -0,0 +1,73 @@
+#lang racket
+
+(provide (struct-out complex) parse eval)
+
+(struct complex (re im) #:transparent)
+
+(define value?
+  complex?)
+
+(define (comp-plus x y)
+  (let ((x-re (complex-re x))
+        (x-im (complex-im x))
+        (y-re (complex-re y))
+        (y-im (complex-im y)))
+    (complex (+ x-re y-re) (+ x-im y-im))))
+
+(define (comp-minus x y)
+  (let ((x-re (complex-re x))
+        (x-im (complex-im x))
+        (y-re (complex-re y))
+        (y-im (complex-im y)))
+    (complex (- x-re y-re) (- x-im y-im))))
+
+(define (comp-mult x y)
+  (let ((x-re (complex-re x))
+        (x-im (complex-im x))
+        (y-re (complex-re y))
+        (y-im (complex-im y)))
+    (complex (- (* x-re y-re) (* x-im y-im)) (+ (* x-re y-im) (* x-im y-re)))))
+
+(define (comp-mod2 x)
+  (let ((x-re (complex-re x))
+        (x-im (complex-im x)))
+    (complex (+ (* x-re x-re) (* x-im x-im)) 0)))
+
+(define (comp-mod x)
+  (let ((mod2 (comp-mod2 x))
+        (x-re (complex-re x)))
+    (complex (sqrt x-re) 0)))
+
+(define (comp-div x y)
+  (let* ((mod2 (complex-re (comp-mod2 y)))
+        (x-re (complex-re x))
+        (x-im (complex-im x))
+        (y-re (complex-re y))
+        (y-im (complex-im y))
+        (real (+ (* x-re y-re) (* x-im y-im)))
+        (imag (- (* x-im y-re) (* x-re y-im))))
+    (complex (/ real mod2) (/ imag mod2))))
+  
+
+;; Ponizej znajduje sie interpreter zwyklych wyrazen arytmetycznych.
+;; Zadanie to zmodyfikowac go tak, by dzialal z liczbami zespolonymi.
+
+(struct const (val)    #:transparent)
+(struct binop (op l r) #:transparent)
+
+(define (imaginary-unit? c)
+  (eq? c 'i))
+
+(define (op->proc op)
+  (match op ['+ comp-plus] ['- comp-minus] ['* comp-mult] ['/ comp-div]))
+
+(define (eval e)
+  (match e
+    [(const n) n]
+    [(binop op l r) ((op->proc op) (eval l) (eval r))]))
+
+(define (parse q)
+  (cond [(number? q) (const (complex q 0))]
+        [(imaginary-unit? q) (const (complex 0 1))]
+        [(and (list? q) (eq? (length q) 3) (symbol? (first q)))
+         (binop (first q) (parse (second q)) (parse (third q)))]))
+\ No newline at end of file
diff --git a/semestr-2/racket/lista6/zad11/solution.bak b/semestr-2/racket/lista6/zad11/solution.bak
new file mode 100644
index 0000000..f449481
--- /dev/null
+++ b/semestr-2/racket/lista6/zad11/solution.bak
@@ -0,0 +1,36 @@
+#lang racket
+
+(provide (struct-out const) (struct-out binop) rpn->arith)
+
+;; -------------------------------
+;; Wyrazenia w odwr. not. polskiej
+;; -------------------------------
+
+(define (rpn-expr? e)
+  (and (list? e)
+       (pair? e)
+       (andmap (lambda (x) (or (number? x) (member x '(+ - * /))))
+               e)))
+
+;; ----------------------
+;; Wyrazenia arytmetyczne
+;; ----------------------
+
+(struct const (val)    #:transparent)
+(struct binop (op l r) #:transparent)
+
+(define (arith-expr? e)
+  (match e
+    [(const n) (number? n)]
+    [(binop op l r)
+     (and (symbol? op) (arith-expr? l) (arith-expr? r))]
+    [_ false]))
+
+;; ----------
+;; Kompilacja
+;; ----------
+
+(define (rpn->arith e)
+  (error "TODO: Uzupelnij tutaj"))
+
+; Mozesz tez dodac jakies procedury pomocnicze i testy
+\ No newline at end of file
diff --git a/semestr-2/racket/lista6/zad11/solution.rkt b/semestr-2/racket/lista6/zad11/solution.rkt
new file mode 100644
index 0000000..a44afe4
--- /dev/null
+++ b/semestr-2/racket/lista6/zad11/solution.rkt
@@ -0,0 +1,58 @@
+#lang racket
+
+(provide (struct-out const) (struct-out binop) rpn->arith)
+
+;; -------------------------------
+;; Wyrazenia w odwr. not. polskiej
+;; -------------------------------
+
+(define (rpn-expr? e)
+  (and (list? e)
+       (pair? e)
+       (andmap (lambda (x) (or (number? x) (member x '(+ - * /))))
+               e)))
+
+;; ----------------------
+;; Wyrazenia arytmetyczne
+;; ----------------------
+
+(struct const (val)    #:transparent)
+(struct binop (op l r) #:transparent)
+
+(define (arith-expr? e)
+  (match e
+    [(const n) (number? n)]
+    [(binop op l r)
+     (and (symbol? op) (arith-expr? l) (arith-expr? r))]
+    [_ false]))
+
+;; ----------
+;; Kompilacja
+;; ----------
+
+(struct stack (xs))
+
+(define empty-stack (stack null))
+(define (empty-stack? s) (null? (stack-xs s)))
+(define (top s) (car (stack-xs s)))
+(define (push a s) (stack (cons a (stack-xs s))))
+(define (pop s) (stack (cdr (stack-xs s))))
+
+(define (op->proc op)
+  (match op ['+ +] ['- -] ['* *] ['/ /]))
+
+(define (eval-am e s)
+  (cond [(null? e)
+         (top s)]
+        [(number? (car e))
+         (eval-am (cdr e) (push (const (car e)) s))]
+        [(symbol? (car e))
+         (eval-am (cdr e)
+                  (push (binop (car e) (top (pop s)) (top s))
+                        (pop (pop s))))]))
+
+(define (rpn->arith e)
+  (eval-am e empty-stack))
+  
+
+; Mozesz tez dodac jakies procedury pomocnicze i testy
+\ No newline at end of file