tasks a-s

Task/Polymorphism/OCaml/polymorphism.ocaml

@@ -0,0 +1,33 @@
+class point ?(x=0.0) ?(y=0.0) () = (* extra () used to erase the optional parameters *)
+object (self)
+  val mutable x = x
+  val mutable y = y
+
+  method x = x
+  method y = y
+  method set_x x' = x <- x'
+  method set_y y' = y <- y'
+  method print = Printf.sprintf "Point (%f, %f)" x y
+  method copy = {< >}
+end
+
+class circle ?(r=1.0) ?(x=0.0) ?(y=0.0) () =
+object (self)
+  inherit point ~x:x ~y:y ()
+  val mutable r = r
+
+  method r = r
+  method set_r r' = r <- r'
+  method print = Printf.sprintf "Circle (%f, %f, %f)" r x y
+end
+
+let print x = print_endline x#print
+
+let () =
+  let p = new point () in
+  let c = new circle () in
+    print c;
+    print p;
+    c#set_x 10.0;
+    print c;
+    print (new point ~y:2.1 ())