From 9477dbe667f250ecd23f8fc0d56b942191526421 Mon Sep 17 00:00:00 2001
From: Franciszek Malinka <franciszek.malinka@gmail.com>
Date: Thu, 25 Feb 2021 14:42:55 +0100
Subject: Stare semestry, niepoukladane

---
 Semestr 2/racket/lista5/props.rkt | 52 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 Semestr 2/racket/lista5/props.rkt

(limited to 'Semestr 2/racket/lista5/props.rkt')

diff --git a/Semestr 2/racket/lista5/props.rkt b/Semestr 2/racket/lista5/props.rkt
new file mode 100644
index 0000000..204b108
--- /dev/null
+++ b/Semestr 2/racket/lista5/props.rkt	
@@ -0,0 +1,52 @@
+#lang racket
+
+(provide conj conj-left conj-right conj?
+         disj disj-left disj-right disj?
+         neg neg-subf neg?
+         var?)
+
+
+(define (conj p q)
+  (list 'conj p q))
+
+(define (conj-left f)
+  (second f))
+
+(define (conj-right f)
+  (third f))
+
+(define (conj? t)
+  (and (list? t)
+        (= 3 (length t))
+        (eq? 'conj (car t))))
+
+
+(define (disj p q)
+  (list 'disj p q))
+
+(define (disj-left f)
+  (second f))
+
+(define (disj-right f)
+  (third f))
+
+(define (disj? t)
+  (and (list? t)
+        (= 3 (length t))
+        (eq? 'disj (car t))))
+
+
+(define (neg x)
+  (list 'neg x))
+
+(define (neg-subf x)
+  (second x))
+
+(define (neg? t)
+  (and (list? t)
+        (= 2 (length t))
+        (eq? 'neg (car t))))
+
+
+(define (var? t)
+  (symbol? t))
-- 
cgit v1.2.3