NL file format with .nl extension

samples/NewLisp/queens.nl

@@ -0,0 +1,49 @@
+#!/usr/bin/env newlisp
+
+(constant 'NUM 8)
+
+(define (intersects? q1 q2)
+	(or 
+		(= (q1 0) (q2 0)) 
+		(= (q1 1) (q2 1))
+		(= (abs (- (q1 0) (q2 0))) (abs (- (q1 1) (q2 1))))))
+
+(define (variant? alist)
+	(set 'logic nil)
+	(cond
+		((= (length alist) 1) true)
+		((> (length alist) 1)
+			(while (> (length alist) 1)
+				(set 'q (pop alist -1))
+				(dolist (el alist)
+					(push 
+						(intersects? 
+							(list q (inc (length alist)))
+							(list el (+ 1 $idx)))
+					logic -1)))
+			(not (apply or logic)))))
+
+(define (fork-by-line alist)
+	(let (res '())
+		(dolist (i (sequence 1 NUM))
+			(set 'tmp alist)
+			(push i tmp -1)
+			(setf res (push tmp res -1)))
+		res))
+
+(define (find-variants num)
+	(let (res '())
+		(cond 
+			((< num 1) 
+				(begin (println "num < 1") (exit)))
+			((= num 1) 
+				(dolist (i (sequence 1 NUM)) (push (list i) res -1)))
+			((> num 1) 
+				(dolist (v (find-variants (dec num))) 
+					(set 'passed (filter variant? (fork-by-line v)))
+					(if (not (empty? passed)) (extend res passed)))))
+		res))
+		
+(set 'solutions (find-variants NUM))
+(println (length solutions))
+;;(exit)