adding a debugprint statement in the il to make it easier for me to trace what's happening

assemble.rkt

@@ -129,6 +129,8 @@ EOF
                        (assemble-label (make-Label (LinkedLabel-label stmt)))
                        (assemble-label (make-Label (LinkedLabel-linked-to stmt))))
               (next)]
+             [(DebugPrint? stmt)
+              (next)]
              [(AssignImmediateStatement? stmt)
               (next)]
              [(AssignPrimOpStatement? stmt)
@@ -177,6 +179,8 @@ EOF
                (format "~a" stmt))
        "")
    (cond
+     [(DebugPrint? stmt)
+      (format "MACHINE.params.currentOutputPort.write(~a);" (assemble-oparg (DebugPrint-value stmt)))]
      [(AssignImmediateStatement? stmt)
       (let: ([t : String (assemble-target (AssignImmediateStatement-target stmt))]
              [v : OpArg (AssignImmediateStatement-value stmt)])

collect-jump-targets.rkt

@@ -34,6 +34,8 @@
    [(LinkedLabel? stmt)
     (list (LinkedLabel-label stmt)
 	  (LinkedLabel-linked-to stmt))]
+   [(DebugPrint? stmt)
+    empty]
    [(AssignImmediateStatement? stmt)
     (let: ([v : OpArg (AssignImmediateStatement-value stmt)])
 	  (collect-input v))]

il-structs.rkt

@@ -120,7 +120,14 @@
                                  PushControlFrame/Call
                                  PushControlFrame/Prompt
 
-                                 PopControlFrame))
+                                 PopControlFrame
+                                 
+                                 DebugPrint))
+
+
+;; Debug print statement.
+(define-struct: DebugPrint ([value : OpArg])
+  #:transparent)
 
 
 (define-type Statement (U UnlabeledStatement

optimize-il.rkt

@@ -62,6 +62,9 @@
     [(LinkedLabel? stmt)
      #f]
     
+    [(DebugPrint? stmt)
+     #f]
+    
     [(AssignImmediateStatement? stmt)
      (equal? (AssignImmediateStatement-target stmt)
              (AssignImmediateStatement-value stmt))]

simulator.rkt

@@ -96,6 +96,10 @@
                      'ok]
                     [(LinkedLabel? i)
                      'ok]
+                    [(DebugPrint? i)
+                     ;; Hack: just to monitor evaluation.
+                     (displayln (evaluate-oparg m (DebugPrint-value i)))
+                     'ok]
                     [(AssignImmediateStatement? i)
                      (step-assign-immediate! m i)]
                     [(AssignPrimOpStatement? i)