September 2017 Update

Task/Polymorphism/Zkl/polymorphism.zkl

@@ -0,0 +1,27 @@
+class Point{var x,y;
+   fcn init(xyOrPoint=0,_=0){
+      if(Point.isInstanceOf(xyOrPoint)) set(xyOrPoint);
+      else x,y=vm.arglist.apply("toFloat")}
+   fcn set(p){x=p.x;y=p.y}
+   fcn toString{"(%d,%d)".fmt(x,y)}
+}
+class Circle{var center, radius;
+   fcn init(a=0.0,b=0.0,r=1.0){
+      switch [arglist]{
+         case(Circle){ center=Point(a.center); radius=a.radius }
+	 case(Point) { center=Point(a); radius=b.toFloat(); }
+	 else { center=Point(a,b); radius=r.toFloat(); }
+      }
+   }
+   fcn copy{self(self)}
+   fcn toString{"(%s,%d)".fmt(center.toString(),radius)}
+}
+   // see if various constructors work
+Point(); Point(1); Point(1,2), Point(Point());
+Circle(); Circle(1); Circle(1,2); Circle(1,2,3);
+Circle(Point()); Circle(Point(),1);
+Circle(Circle());
+
+c:=Circle(1,2,3);
+c.println(); c.center.println();
+c.copy().println();