format_args_ordered_low_overhead

tests/performance/compare_algo/nqueens/format_args_ordered.metta

@@ -0,0 +1,35 @@
+; (= (select $x) ((car-atom $x) (cdr-atom $x)))
+; (= (select $x) (let* (($y (car-atom $x)) ($z (cdr-atom $x)) (($u $v) (select $z))) ($u (cons-atom $y $v))))
+
+(= (select $x) (if (== $x ()) (empty) ((car-atom $x) (cdr-atom $x))))
+(= (select $x) (if (== $x ()) (empty) (let* (($y (car-atom $x)) ($z (cdr-atom $x)) (($u $v) (select $z))) ($u (cons-atom $y $v)))))
+
+(= (range $x $y)
+    (if (== $x $y)
+        ($x)
+        (let $z (range (+ $x 1) $y)
+            (cons-atom $x $z))))
+
+(= (not_attack $q $d $s)
+    (if (== $s ())
+        True
+        (let* (($h (car-atom $s)) ($t (cdr-atom $s)))
+            (if (or (== $q $h) (or (== $q (+ $d $h)) (== $h (+ $q $d)))) False
+                (not_attack $q (+ $d 1) $t)))))
+
+(= (nqueens_aux $unplaced $safe)
+    (if (== $unplaced ())
+        $safe
+        (let ($q $r) (select $unplaced)
+            (if (not_attack $q 1 $safe)
+                (let $safeext (cons-atom $q $safe)
+                (nqueens_aux $r $safeext))
+                (empty)))))
+
+(= (nqueens $n)
+    (let $r (range 1 $n) (nqueens_aux $r ())))
+
+; !(call-string ":- time(findall(X,mc__nqueens(12,X),_)).")
+
+!(nqueens 7)
+