mv lab 07 to 06

lectures/09/list_monad.ml

@@ -0,0 +1,18 @@
+let return x = [x]
+
+let ( >>= ) l f = List.concat_map f l
+
+let gaurd cond l =
+  if cond then l else []
+
+let multiply_to n =
+  List.init n ((+) 1) >>= fun x ->
+    List.init n ((+) 1) >>= fun y ->
+      gaurd (x * y = n) [(x, y)]
+
+let ( let* ) = ( >>= )
+
+let multiply_to' n =
+  let* x = List.init n ((+) 1) in
+  let* y = List.init n ((+) 1) in
+  if x * y = n then [(x, y)] else []