1 files changed, 32 insertions, 0 deletions
diff --git a/js/games/nluqo.github.io/~bh/61a-pages/Lectures/3.0/count.scm b/js/games/nluqo.github.io/~bh/61a-pages/Lectures/3.0/count.scm
new file mode 100644
index 0000000..b68ff2d
--- /dev/null
+++ b/js/games/nluqo.github.io/~bh/61a-pages/Lectures/3.0/count.scm
@@ -0,0 +1,32 @@
+(define-class (counter)
+  (instance-vars (count 0))
+  (method (next)
+    (set! count (+ count 1))
+    count) )
+
+(define-class (counter2)
+  (instance-vars (count 0))
+  (class-vars (total 0))
+  (method (next)
+    (set! total (+ total 1))
+    (set! count (+ count 1))
+    (list count total)))
+
+(define-class (counter3)
+  (instance-vars (count 0))
+  (class-vars (total 0) (counters '()))
+  (initialize (set! counters (cons self counters)))
+  (method (next)
+    (set! total (+ total 1))
+    (set! count (+ count 1))
+    (list count total)))
+
+(define c11 (instantiate counter))
+(define c12 (instantiate counter))
+
+(define c21 (instantiate counter2))
+(define c22 (instantiate counter2))
+
+(define c31 (instantiate counter3))
+(define c32 (instantiate counter3))
+