diff --git a/assemble.rkt b/assemble.rkt
index 86cb1d5..0ea5aa8 100644
--- a/assemble.rkt
+++ b/assemble.rkt
@@ -192,12 +192,16 @@
   (let: loop : String ([val : Any (Const-const stmt)])
         (cond [(symbol? val)
                (format "~s" (symbol->string val))]
-              [(list? val)
-               (format "_list(~a)" (string-join (map loop val)
-                                                ","))]
+              [(pair? val)
+               (format "[~a, ~a]" 
+                       (loop (car val))
+                       (loop (cdr val)))]
+              [(empty? val)
+               (format "undefined")]
               [else
                (format "~s" val)])))
 
+
 (: assemble-op-expression ((U PrimitiveOperator TestOperator) (Listof OpArg) -> String))
 (define (assemble-op-expression op-name inputs)
   (let ([assembled-inputs (map assemble-input inputs)])
@@ -250,13 +254,10 @@
                (first assembled-inputs))]
       [(extend-environment/prefix)
        (format "new ExtendedPrefixEnvironment(~a, ~a)"
-               (second assembled-inputs)
-               (first assembled-inputs))]
-      #;[(lookup-variable-value)
-       (format "((~a).globalBindings[~a])"
                (second assembled-inputs)
                (first assembled-inputs))])))
 
+
 (: assemble-op-statement (PerformOperator (Listof OpArg) -> String))
 (define (assemble-op-statement op-name inputs)
   (let ([assembled-inputs (map assemble-input inputs)])
diff --git a/compile.rkt b/compile.rkt
index c6e03a6..fa36976 100644
--- a/compile.rkt
+++ b/compile.rkt
@@ -80,7 +80,7 @@
                     (make-instruction-sequence
                      '()
                      (list target)
-                     `(,(make-AssignImmediateStatement target (make-Const exp))))))
+                     `(,(make-AssignImmediateStatement target (make-Const (Constant-v exp)))))))
 
 (: compile-quoted (Quote CompileTimeEnvironment Target Linkage -> InstructionSequence))
 (define (compile-quoted exp cenv target linkage)
diff --git a/runtime.js b/runtime.js
index 68e23bd..9a44291 100644
--- a/runtime.js
+++ b/runtime.js
@@ -7,44 +7,59 @@
 // function closures are Closures
 // primitive procedures are regular functions.
 
-var TopEnvironment = function() {
-    this.globalBindings = {
-	'=': function(argl) {
-            return argl[0] === argl[1][0];
-        },
+var Primitives = {
+    '=': function(argl) {
+        return argl[0] === argl[1][0];
+    },
+    
+    '+': function(argl) {
+        return argl[0] + argl[1][0];
+    },
+    
+    '*': function(argl) {
+        return argl[0] * argl[1][0];
+    },
+    
+    '-': function(argl) {
+        return argl[0] - argl[1][0];
+    },
+    
+    '/': function(argl) {
+	return argl[0] / argl[1][0];
+    }
+};
 
-        '+': function(argl) {
-            return argl[0] + argl[1][0];
-        },
 
-        '*': function(argl) {
-            return argl[0] * argl[1][0];
-        },
-
-	'-': function(argl) {
-            return argl[0] - argl[1][0];
-        },
-	
-	'/': function(argl) {
-	    return argl[0] / argl[1][0];
-	}
-    };
+var TopEnvironment = function() {    
     this.valss = [];
 };
 
+
 var ExtendedPrefixEnvironment = function(parent, vs) {
     var vals = [];
+    this.names = [];
     while(vs) {
-	if (parent.globalBindings[vs[0]]) {
-	    vals.push(parent.globalBindings[vs[0]]);
+	this.names.push(vs[0]);
+	if (Primitives[vs[0]]) {
+	    vals.push(Primitives[vs[0]]);
 	} else {
 	    vals.push(undefined);
 	}	
 	vs = vs[1];
     }
+
     this.valss = parent.valss.slice();
     this.valss.unshift(vals);
-    this.globalBindings = parent.globalBindings;
+};
+
+ExtendedPrefixEnvironment.prototype.lookup = function(name) {
+    var i;
+    for (i = 0; i < this.names.length; i++) {
+	if (this.names[i] === name) {
+	    return this.valss[0][i];
+	}
+    }
+    return undefined;
 };
 
 var ExtendedEnvironment = function(parent, vs) {
@@ -55,7 +70,6 @@ var ExtendedEnvironment = function(parent, vs) {
     }
     this.valss = parent.valss.slice();
     this.valss.unshift(vals);
-    this.globalBindings = parent.globalBindings;
 };
 
 
diff --git a/typed-structs.rkt b/typed-structs.rkt
index 339c973..1766012 100644
--- a/typed-structs.rkt
+++ b/typed-structs.rkt
@@ -63,9 +63,12 @@
 (define-struct: SaveStatement ([reg : Symbol]) #:transparent)
 (define-struct: RestoreStatement ([reg : Symbol]) #:transparent)
 
-(define-struct: Label ([name : Symbol]))
-(define-struct: Reg ([name : Symbol]))
-(define-struct: Const ([const : Any]))
+(define-struct: Label ([name : Symbol])
+  #:transparent)
+(define-struct: Reg ([name : Symbol])
+  #:transparent)
+(define-struct: Const ([const : Any])
+  #:transparent)
 
 (define-type OpArg (U Const Label Reg))
 
@@ -144,7 +147,8 @@
 ;;  Lexical environments
 
 ;; A toplevel prefix contains a list of toplevel variables.
-(define-struct: Prefix ([names : (Listof Symbol)]))
+(define-struct: Prefix ([names : (Listof Symbol)])
+  #:transparent)
 
 ;; A compile-time environment is a (listof (listof symbol)).
 ;; A lexical address is either a 2-tuple (depth pos), or 'not-found.
@@ -153,7 +157,9 @@
 (define-type LexicalAddress (U LocalAddress PrefixAddress))
 
 (define-struct: LocalAddress ([depth : Natural]
-                              [pos : Natural]))
+                              [pos : Natural])
+  #:transparent)
 (define-struct: PrefixAddress ([depth : Natural]
                                [pos : Natural]
-                               [name : Symbol]))
\ No newline at end of file
+                               [name : Symbol])
+  #:transparent)
\ No newline at end of file