diff --git a/simulator-structs.rkt b/simulator-structs.rkt
new file mode 100644
index 0000000..dd98d8a
--- /dev/null
+++ b/simulator-structs.rkt
@@ -0,0 +1,20 @@
+#lang typed/racket/base
+
+(provide (all-defined-out))
+
+(require "il-structs.rkt")
+
+
+(define-struct: machine ([val : Any]
+                         [proc : Any]
+                         [env : (Listof Any)]
+                         [control : (Listof frame)]
+
+                         [pc : Natural]                  ;; program counter
+                         [text : (Vectorof Statement)]   ;; text of the program
+                         ))
+
+
+(define-struct: frame ([return : Symbol]))
+
+
diff --git a/simulator.rkt b/simulator.rkt
new file mode 100644
index 0000000..16d0e44
--- /dev/null
+++ b/simulator.rkt
@@ -0,0 +1,76 @@
+#lang typed/racket/base
+
+;; An evaluator for the intermediate language, so I can do experiments.
+
+(require "il-structs.rkt"
+         "simulator-structs.rkt"
+         racket/list
+         racket/match)
+
+(provide new-machine can-step? step)
+
+
+(: new-machine ((Listof Statement) -> machine))
+(define (new-machine program-text)
+  (make-machine (void) (void) '() '() 0 (list->vector program-text)))
+
+
+(: can-step? (machine -> Boolean))
+(define (can-step? m)
+  #t)
+
+
+(: step (machine -> machine))
+(define (step m)
+  (match m
+    [(struct machine (val proc env control pc text))
+     m
+     ]))
+
+(: val-update (machine Any -> machine))
+(define (val-update m v)
+  (match m
+    [(struct machine (val proc env control pc text))
+     (make-machine v proc env control pc text)]))
+
+(: proc-update (machine Any -> machine))
+(define (proc-update m v)
+    (match m
+    [(struct machine (val proc env control pc text))
+     (make-machine val v env control pc text)]))
+
+(: env-push (machine Any -> machine))
+(define (env-push m v)
+  (match m
+    [(struct machine (val proc env control pc text))
+     (make-machine val proc (cons v env) control pc text)]))
+
+(: env-ref (machine Natural -> Any))
+(define (env-ref m i)  
+  (match m
+    [(struct machine (val proc env control pc text))
+     (list-ref env i)]))
+
+(: env-mutate (machine Natural Any -> machine))
+(define (env-mutate m i v)
+  (match m
+    [(struct machine (val proc env control pc text))
+     (make-machine val proc (list-replace env i v) control pc text)]))
+
+(: list-replace (All (A) (Listof A) Natural A -> (Listof A)))
+(define (list-replace l i v)
+  (cond
+    [(= i 0)
+     (cons v (rest l))]
+    [else
+     (cons (first l)
+           (list-replace (rest l) (sub1 i) v))]))
+
+
+(: env-pop (machine Natural Natural -> machine))
+(define (env-pop m n skip)     
+  (match m
+    [(struct machine (val proc env control pc text))
+     (make-machine val proc (append (take env skip)
+                                    (drop env (+ skip n)))
+                   control pc text)]))
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