new tasks

Task/Classes/Racket/classes.rkt

@@ -0,0 +1,15 @@
+#lang racket
+
+(define fish%
+  (class object%
+    (super-new)
+
+    ;; an instance variable & constructor argument
+    (init-field size)
+
+    ;; a new method
+    (define/public (eat)
+      (displayln "gulp!"))))
+
+;; constructing an instance
+(new fish% [size 50])