misc: starting Turing Machine in Racket.

misc/turing.rkt

@@ -0,0 +1,18 @@
+#lang racket
+
+;;; a turing machine implementation
+(define tape (make-hash))
+
+(define (lookup position)
+  (unless (hash-has-key? tape position)
+    (hash-set! tape position 0))
+  (hash-ref tape position))
+
+(define turing-machine%
+  (class object%
+    (init)
+    (define tape (make-hash))
+    (define head 0)
+    (define current-state #f)
+    (define state-table)
+    (super-new)))