diff --git a/whalesong/parser/parse-bytecode-5.3.3.7.rkt b/whalesong/parser/parse-bytecode-5.3.3.7.rkt
index 4d515fd..993ad6b 100644
--- a/whalesong/parser/parse-bytecode-5.3.3.7.rkt
+++ b/whalesong/parser/parse-bytecode-5.3.3.7.rkt
@@ -228,6 +228,7 @@
            (make-ModuleLocator (rewrite-path resolved-path-name)
                                (normalize-path resolved-path-name))]
           [else
+           (displayln (list 'wrap-module-name resolved-path-name rewritten-path))
            (error 'wrap-module-name "Unable to resolve module path ~s."
                   resolved-path-name)]))]))
    
diff --git a/whalesong/selfhost/js-assembler/assemble-helpers.rkt b/whalesong/selfhost/js-assembler/assemble-helpers.rkt
new file mode 100644
index 0000000..61eca21
--- /dev/null
+++ b/whalesong/selfhost/js-assembler/assemble-helpers.rkt
@@ -0,0 +1,527 @@
+#lang whalesong (require "../selfhost-lang.rkt" "../selfhost-strings.rkt")
+; #lang typed/racket/base
+
+(require "../compiler/il-structs.rkt"
+         "../compiler/expression-structs.rkt"
+         "../compiler/lexical-structs.rkt"
+         "../compiler/arity-structs.rkt"
+         "assemble-structs.rkt"
+         racket/list
+         ; racket/string
+         racket/match)
+
+
+; (require/typed net/base64 [base64-encode (Bytes -> Bytes)])
+(require "../base64.rkt") ; base64-encode : string -> string
+
+(provide assemble-oparg
+         assemble-target
+         assemble-const
+         assemble-lexical-reference
+         assemble-prefix-reference
+         assemble-whole-prefix-reference
+         assemble-reg
+         munge-label-name
+         assemble-label
+         assemble-listof-assembled-values
+	 assemble-default-continuation-prompt-tag
+	 assemble-env-reference/closure-capture
+	 assemble-arity
+	 assemble-jump
+	 assemble-display-name
+	 assemble-location
+         assemble-numeric-constant
+         assemble-module-variable-ref
+         
+         block-looks-like-context-expected-values?
+         block-looks-like-pop-multiple-values-and-continue?
+
+         current-interned-symbol-table
+         assemble-current-interned-symbol-table
+         )
+
+#;(require/typed typed/racket/base
+                 [regexp-split (Regexp String -> (Listof String))])
+
+
+(: assemble-oparg (OpArg Blockht -> String))
+(define (assemble-oparg v blockht)
+  (cond 
+    [(Reg? v)
+     (assemble-reg v)]
+    [(Label? v)
+     (assemble-label v)]
+    [(Const? v)
+     (assemble-const v)]
+    [(EnvLexicalReference? v)
+     (assemble-lexical-reference v)]
+    [(EnvPrefixReference? v)
+     (assemble-prefix-reference v)]
+    [(EnvWholePrefixReference? v)
+     (assemble-whole-prefix-reference v)]
+    [(SubtractArg? v)
+     (assemble-subtractarg v blockht)]
+    [(ControlStackLabel? v)
+     (assemble-control-stack-label v)]
+    [(ControlStackLabel/MultipleValueReturn? v)
+     (assemble-control-stack-label/multiple-value-return v)]
+    [(ControlFrameTemporary? v)
+     (assemble-control-frame-temporary v)]
+    [(CompiledProcedureEntry? v)
+     (assemble-compiled-procedure-entry v blockht)]
+    [(CompiledProcedureClosureReference? v)
+     (assemble-compiled-procedure-closure-reference v blockht)]
+    [(PrimitiveKernelValue? v)
+     (assemble-primitive-kernel-value v)]
+    [(ModuleEntry? v)
+     (assemble-module-entry v)]
+    [(ModulePredicate? v)
+     (assemble-module-predicate v)]
+    [(VariableReference? v)
+     (assemble-variable-reference v)]))
+
+
+
+
+
+
+(: assemble-target (Target -> (String -> String)))
+(define (assemble-target target)
+  (cond
+   [(PrimitivesReference? target)
+    (lambda (rhs) ; ([rhs : String])
+             (format "RT.Primitives[~s]=RT.Primitives[~s]||~a;"
+                     (symbol->string (PrimitivesReference-name target))
+                     (symbol->string (PrimitivesReference-name target))
+                     rhs))]
+   [(ModuleVariable? target)
+    (lambda (rhs) ; ([rhs : String])
+             (format "M.modules[~s].getExports().set(~s,~s);"
+                     (symbol->string (ModuleLocator-name (ModuleVariable-module-name target)))
+                     (symbol->string (ModuleVariable-name target))
+                     rhs))]
+   [else
+    (lambda (rhs) ; ([rhs : String])
+             (format "~a=~a;"
+                     (ann (cond
+                            [(eq? target 'proc)
+                             "M.p"]
+                            [(eq? target 'val)
+                             "M.v"]
+                            [(eq? target 'argcount)
+                             "M.a"]
+                            [(EnvLexicalReference? target)
+                             (assemble-lexical-reference target)]
+                            [(EnvPrefixReference? target)
+                             (assemble-prefix-reference target)]
+                            [(ControlFrameTemporary? target)
+                             (assemble-control-frame-temporary target)]
+                            [(GlobalsReference? target)
+                             (format "M.globals[~s]" (symbol->string (GlobalsReference-name target)))]
+                            [(ModulePrefixTarget? target)
+                             (format "M.modules[~s].prefix"
+                                     (symbol->string (ModuleLocator-name (ModulePrefixTarget-path target))))])
+                           String)
+                     rhs))]))
+
+
+
+(: assemble-control-frame-temporary (ControlFrameTemporary -> String))
+(define (assemble-control-frame-temporary t)
+  (format "M.c[M.c.length-1].~a"
+          (ControlFrameTemporary-name t)))
+
+
+(: current-interned-symbol-table (Parameterof (HashTable Symbol Symbol)))
+(define current-interned-symbol-table
+  (make-parameter ((inst make-hasheq Symbol Symbol))))
+
+
+(: assemble-current-interned-symbol-table (-> String))
+(define (assemble-current-interned-symbol-table)
+  (string-join (hash-map
+                  (current-interned-symbol-table)
+                  (lambda (a-symbol variable-name) ; ([a-symbol : Symbol] [variable-name : Symbol]) 
+                    (format "var ~a=RT.makeSymbol(~s);"
+                            variable-name
+                            (symbol->string a-symbol))))
+                 "\n"))
+  
+;; fixme: use js->string
+(: assemble-const (Const -> String))
+(define (assemble-const stmt)
+  (let loop ; : String ([val : const-value (Const-const stmt)])
+    ([val (Const-const stmt)])
+        (cond [(symbol? val)
+               (define intern-var (hash-ref (current-interned-symbol-table)
+                                            val
+                                            (lambda ()
+                                              (define fresh (gensym 'sym))
+                                              (hash-set! (current-interned-symbol-table) val fresh)
+                                              fresh)))
+               (symbol->string intern-var)
+               ;;(format "RT.makeSymbol(~s)" (symbol->string val))
+               ]
+              [(pair? val)
+               (format "RT.makePair(~a,~a)" 
+                       (loop (car val))
+                       (loop (cdr val)))]
+              [(boolean? val)
+               (if val "true" "false")]
+              [(void? val)
+               "RT.VOID"]
+              [(empty? val)
+               (format "RT.NULL")]
+              [(number? val)
+               (assemble-numeric-constant val)]
+              [(string? val)
+               (format "~s" val)]
+              [(char? val)
+               (format "RT.makeChar(~s)" (string val))]
+              [(bytes? val)
+               ;; This needs to be an array, because this may contain
+               ;; a LOT of elements, and certain JS evaluators will break
+               ;; otherewise.
+               (format "RT.makeBytesFromBase64(~s)"
+                       (bytes->string/utf-8 (base64-encode val)))]
+              [(path? val)
+               (format "RT.makePath(~s)"
+                       (path->string val))]
+              [(vector? val)
+               (format "RT.makeVector([~a])"
+                       (string-join (map loop (vector->list val)) 
+                                    ","))]
+              [(box? val)
+               (format "RT.makeBox(~s)"
+                       (loop (unbox val)))])))
+
+
+
+(: assemble-listof-assembled-values ((Listof String) -> String))
+(define (assemble-listof-assembled-values vals)
+  (let loop ([vals vals])
+    (cond
+      [(empty? vals)
+       "RT.NULL"]
+      [else
+       (format "RT.makePair(~a,~a)" (first vals) (loop (rest vals)))])))
+
+
+
+;; Slightly ridiculous definition, but I need it to get around what appear to
+;; be Typed Racket bugs in its numeric tower.
+; (define-predicate int? Integer)
+(define int? integer?)
+
+
+(: assemble-numeric-constant (Number -> String))
+(define (assemble-numeric-constant a-num)
+
+  (: floating-number->js (Real -> String))
+  (define (floating-number->js a-num)
+    (cond
+     [(eqv? a-num -0.0)
+      "RT.NEGATIVE_ZERO"]
+     [(eqv? a-num +inf.0)
+      "RT.INF"]
+     [(eqv? a-num -inf.0)
+      "RT.NEGATIVE_INF"]
+     [(eqv? a-num +nan.0)
+      "RT.NAN"]
+     [else
+      (string-append "RT.makeFloat(" (number->string a-num) ")")]))
+
+  ;; FIXME: fix the type signature when typed-racket isn't breaking on
+  ;; (define-predicate ExactRational? (U Exact-Rational))
+  (: rational-number->js (Real -> String))
+  (define (rational-number->js a-num)
+    (cond [(= (denominator a-num) 1)
+           (string-append (integer->js (ensure-integer (numerator a-num))))]
+          [else
+           (string-append "RT.makeRational("
+                          (integer->js (ensure-integer (numerator a-num)))
+                          ","
+                          (integer->js (ensure-integer (denominator a-num)))
+                          ")")]))
+
+  
+  (: ensure-integer (Any -> Integer))
+  (define (ensure-integer x)
+    (if (int? x)
+        x
+        (error "not an integer: ~e" x)))
+  
+
+
+  (: integer->js (Integer -> String))
+  (define (integer->js an-int)
+    (cond
+     ;; non-overflow case
+     [(< (abs an-int) 9e15)
+      (number->string an-int)]
+     ;; overflow case
+     [else
+      (string-append "RT.makeBignum("
+                     (format "~s" (number->string an-int))
+                     ")")]))
+
+  (cond 
+   [(and (exact? a-num) (rational? a-num))
+    (rational-number->js a-num)]
+   
+   [(real? a-num)
+    (floating-number->js a-num)]
+   
+   [(complex? a-num)
+    (string-append "RT.makeComplex("
+                   (assemble-numeric-constant (real-part a-num))
+                   ","
+                   (assemble-numeric-constant (imag-part a-num))
+                   ")")]))
+
+
+(: assemble-lexical-reference (EnvLexicalReference -> String))
+(define (assemble-lexical-reference a-lex-ref)
+  (if (EnvLexicalReference-unbox? a-lex-ref)
+      (format "M.e[M.e.length-~a][0]"
+              (add1 (EnvLexicalReference-depth a-lex-ref)))
+      (format "M.e[M.e.length-~a]"
+              (add1 (EnvLexicalReference-depth a-lex-ref)))))
+
+
+(: assemble-prefix-reference (EnvPrefixReference -> String))
+(define (assemble-prefix-reference a-ref)
+  (cond
+   [(EnvPrefixReference-modvar? a-ref)
+    (format "M.e[M.e.length-~a][~a][0][M.e[M.e.length-~a][~a][1]]"
+            (add1 (EnvPrefixReference-depth a-ref))
+            (EnvPrefixReference-pos a-ref)
+            (add1 (EnvPrefixReference-depth a-ref))
+            (EnvPrefixReference-pos a-ref))]
+   [else
+    (format "M.e[M.e.length-~a][~a]"
+            (add1 (EnvPrefixReference-depth a-ref))
+            (EnvPrefixReference-pos a-ref))]))
+
+(: assemble-whole-prefix-reference (EnvWholePrefixReference -> String))
+(define (assemble-whole-prefix-reference a-prefix-ref)
+  (format "M.e[M.e.length-~a]"
+          (add1 (EnvWholePrefixReference-depth a-prefix-ref))))
+
+
+(: assemble-reg (Reg -> String))
+(define (assemble-reg a-reg)
+  (let ([name (Reg-name a-reg)])
+    (cond
+     [(eq? name 'proc)
+      "M.p"]
+     [(eq? name 'val)
+      "M.v"]
+     [(eq? name 'argcount)
+      "M.a"])))
+
+
+(: munge-label-name (Label -> String))
+(define (munge-label-name a-label)
+  (define chunks
+    (string-split-at-non-alphanumeric        ; was (regexp-split #rx"[^a-zA-Z0-9]+" ...)
+     (symbol->string (Label-name a-label))))
+  (cond
+   [(empty? chunks)
+    (error "impossible: empty label ~s" a-label)]
+   [(empty? (rest chunks))
+    (string-append "_" (first chunks))]
+   [else
+    (string-append "_"
+                   (first chunks)
+                   (apply string-append (map string-titlecase (rest chunks))))]))
+
+
+
+(: assemble-label (Label -> String))
+(define (assemble-label a-label)
+  (munge-label-name a-label))
+
+
+
+(: assemble-subtractarg (SubtractArg Blockht -> String))
+(define (assemble-subtractarg s blockht)
+  (format "(~a-~a)"
+          (assemble-oparg (SubtractArg-lhs s) blockht)
+          (assemble-oparg (SubtractArg-rhs s) blockht)))
+
+
+(: assemble-control-stack-label (ControlStackLabel -> String))
+(define (assemble-control-stack-label a-csl)
+  "M.c[M.c.length-1].label")
+
+
+(: assemble-control-stack-label/multiple-value-return (ControlStackLabel/MultipleValueReturn -> String))
+(define (assemble-control-stack-label/multiple-value-return a-csl)
+  "(M.c[M.c.length-1].label.mvr||RT.si_context_expected_1)")
+
+
+
+(: assemble-compiled-procedure-entry (CompiledProcedureEntry Blockht -> String))
+(define (assemble-compiled-procedure-entry a-compiled-procedure-entry blockht)
+  (format "(~a).label"
+          (assemble-oparg (CompiledProcedureEntry-proc a-compiled-procedure-entry)
+                          blockht)))
+
+
+(: assemble-compiled-procedure-closure-reference (CompiledProcedureClosureReference Blockht -> String))
+(define (assemble-compiled-procedure-closure-reference a-ref blockht)
+  (format "(~a).closedVals[(~a).closedVals.length - ~a]"
+          (assemble-oparg (CompiledProcedureClosureReference-proc a-ref) blockht)
+          (assemble-oparg (CompiledProcedureClosureReference-proc a-ref) blockht)
+          (add1 (CompiledProcedureClosureReference-n a-ref))))
+
+
+
+(: assemble-default-continuation-prompt-tag (-> String))
+(define (assemble-default-continuation-prompt-tag)
+  "RT.DEFAULT_CONTINUATION_PROMPT_TAG")
+
+
+
+(: assemble-env-reference/closure-capture (Natural -> String))
+;; When we're capturing the values for a closure, we need to not unbox
+;; lexical references: they must remain boxes.  So all we need is 
+;; the depth into the environment.
+(define (assemble-env-reference/closure-capture depth)
+  (format "M.e[M.e.length-~a]"
+          (add1 depth)))
+
+
+
+; (define-predicate natural? Natural)
+
+(: assemble-arity (Arity -> String))
+(define (assemble-arity an-arity)
+  (cond
+   [(natural? an-arity)
+    (number->string an-arity)]
+   [(ArityAtLeast? an-arity)
+    (format "(RT.makeArityAtLeast(~a))"
+            (ArityAtLeast-value an-arity))]
+   [(listof-atomic-arity? an-arity)
+    (assemble-listof-assembled-values
+     (map
+      (lambda (atomic-arity) ; ([atomic-arity : (U Natural ArityAtLeast)])
+	       (cond
+		[(natural? atomic-arity)
+		 (number->string atomic-arity)]
+		[(ArityAtLeast? atomic-arity)
+		 (format "(RT.makeArityAtLeast(~a))"
+                         (ArityAtLeast-value atomic-arity))]))
+      an-arity))]))
+
+
+
+
+
+
+(: assemble-jump (OpArg Blockht -> String))
+(define (assemble-jump target blockht)
+
+  (define (default)
+    (format "return(~a)(M);" (assemble-oparg target blockht)))
+  
+  ;; Optimization: if the target of the jump goes to a block whose
+  ;; only body is a si-context-expected_1, then jump directly to that code.
+  (cond
+   [(Label? target)
+    (define target-block (hash-ref blockht (Label-name target)))
+    (cond
+     [(block-looks-like-context-expected-values? target-block)
+      =>
+      (lambda (expected)
+        (format "RT.si_context_expected(~a)(M);\n" expected))]
+     [else
+      (default)])]
+   [else
+    (default)]))
+
+
+
+(: block-looks-like-context-expected-values? (BasicBlock -> (U Natural False)))
+(define (block-looks-like-context-expected-values? a-block)
+  (match (BasicBlock-stmts a-block)
+    [(list (struct Perform ((struct RaiseContextExpectedValuesError! (expected))))
+           stmts ...)
+     expected]
+    [else
+     #f]))
+
+
+(: block-looks-like-pop-multiple-values-and-continue? (BasicBlock -> (U False)))
+(define (block-looks-like-pop-multiple-values-and-continue? a-block)
+  ;; FIXME!
+  #f)
+
+
+
+
+
+
+(: assemble-display-name ((U Symbol LamPositionalName) -> String))
+(define (assemble-display-name name)
+  (cond
+   [(symbol? name)
+    (format "~s" (symbol->string name))]
+   [(LamPositionalName? name)
+    ;; FIXME: record more interesting information here.
+    (format "~s" (symbol->string (LamPositionalName-name name)))]))
+
+
+
+
+(: assemble-location ((U Reg Label) Blockht -> String))
+(define (assemble-location a-location blockht)
+  (cond
+     [(Reg? a-location)
+      (assemble-reg a-location)]
+     [(Label? a-location)
+      (assemble-label a-location)]))
+
+
+(: assemble-primitive-kernel-value (PrimitiveKernelValue -> String))
+(define (assemble-primitive-kernel-value a-prim)
+  (format "M.primitives[~s]" (symbol->string (PrimitiveKernelValue-id a-prim))))
+
+
+
+(: assemble-module-entry (ModuleEntry -> String))
+(define (assemble-module-entry entry)
+  (format "M.modules[~s].label"
+          (symbol->string (ModuleLocator-name (ModuleEntry-name entry)))))
+
+
+(: assemble-module-variable-ref (ModuleVariable -> String))
+(define (assemble-module-variable-ref var)
+  (format "M.modules[~s].getExports().get(~s)"
+          (symbol->string (ModuleLocator-name (ModuleVariable-module-name var)))
+          (symbol->string (ModuleVariable-name var))))
+
+
+(: assemble-module-predicate (ModulePredicate -> String))
+(define (assemble-module-predicate entry)
+  (define modname (ModulePredicate-module-name entry))
+  (define pred (ModulePredicate-pred entry))
+  (cond
+   [(eq? pred 'invoked?)
+    (format "M.modules[~s].isInvoked"
+            (symbol->string (ModuleLocator-name modname)))]
+
+   [(eq? pred 'linked?)
+    (format "(M.installedModules[~s]!==void(0)&&M.modules[~s]!==undefined)"
+            (symbol->string (ModuleLocator-name modname))
+            (symbol->string (ModuleLocator-name modname)))]))
+
+
+(: assemble-variable-reference (VariableReference -> String))
+(define (assemble-variable-reference varref)
+  (let ([t (VariableReference-toplevel varref)])
+    (format "(new RT.VariableReference(M.e[M.e.length-~a],~a))"
+            (add1 (ToplevelRef-depth t))
+            (ToplevelRef-pos t))))
diff --git a/whalesong/selfhost/selfhost-lang.rkt b/whalesong/selfhost/selfhost-lang.rkt
index ea68ba6..76a2f3f 100644
--- a/whalesong/selfhost/selfhost-lang.rkt
+++ b/whalesong/selfhost/selfhost-lang.rkt
@@ -16,11 +16,13 @@
          sort
          natural?
          vector-copy
+         bytes->string/utf-8 ; is values
+         path->string
          ; no-ops
          :
+         ann
          log-debug
-         ensure-type-subsetof
-         )
+         ensure-type-subsetof)
 
 (require "selfhost-parameters.rkt")
 (require (for-syntax racket/base))
@@ -66,6 +68,7 @@
 (define-syntax (define-type stx) #'(void))
 (define-syntax (: stx) #'(void))
 (define-syntax (ensure-type-subsetof stx) #'(void))
+(define-syntax (ann stx) (syntax-case stx () [(_ expr type) #'expr]))
 
 (define-syntax (inst stx)
   (syntax-case stx ()
@@ -86,3 +89,7 @@
     (vector-set! v j (vector-ref vec i)))
   v)
 
+(define bytes->string/utf-8 values)
+
+(define (path->string x)
+  (error 'todo-implement-me))
\ No newline at end of file
diff --git a/whalesong/selfhost/selfhost-strings.rkt b/whalesong/selfhost/selfhost-strings.rkt
index dfc7921..d614536 100644
--- a/whalesong/selfhost/selfhost-strings.rkt
+++ b/whalesong/selfhost/selfhost-strings.rkt
@@ -1,6 +1,11 @@
 #lang whalesong (require "selfhost-lang.rkt" whalesong/lang/for)
 
-(provide string-replace) ; (string-replace k r s) replace all occurences of k in s with r
+(provide string-replace ; (string-replace k r s) replace all occurences of k in s with r
+         string-split-at-non-alphanumeric
+         string-join
+         string-titlecase)
+
+(define string-titlecase values) ; for now XXX todo: used in munge-label
 
 ; string-index : string string [integer] -> integer
 ;   return the index of the first occurence of k in the string s
@@ -39,13 +44,51 @@
 
 ; Test must evaluate to #t
 #;(and (= (string-index "bar" "foobarbazbar")
-        (string-index "bar" "foobarbazbar" 1)
-        (string-index "bar" "foobarbazbar" 2)
-        (string-index "bar" "foobarbazbar" 3) 
-        3)
-     (= (string-index "bar" "foobarbazbar" 4) 9)
-     (equal? (string-index "bar" "foobarbazbar" 10) #f))
+          (string-index "bar" "foobarbazbar" 1)
+          (string-index "bar" "foobarbazbar" 2)
+          (string-index "bar" "foobarbazbar" 3) 
+          3)
+       (= (string-index "bar" "foobarbazbar" 4) 9)
+       (equal? (string-index "bar" "foobarbazbar" 10) #f))
 
 ; (string-replace "foo" "_" "abfoocdfoooo")
 
+(define non-splitters
+  (let ()
+    (define alpha "qwertyuiopasdfghjklzxcvbnm")
+    (define ALPHA "QWERTYUIOPASDFGHJKLZXCVBNM")
+    (define nums  "0123456789")
+    (string->list (string-append alpha ALPHA nums))))
+
+; (regexp-split #rx"[^a-zA-Z0-9]+" s)
+(define (string-split-at-non-alphanumeric s)
+  (define (splitter? c) (not (memq c non-splitters)))
+  (define chunks
+    (reverse
+     (let loop ([chunks '()] [current '()] [xs (string->list s)])
+       (cond 
+         [(and (empty? xs) (empty? current))
+          chunks]
+         [(empty? xs)
+          (cons (reverse current) chunks)]
+         [(splitter? (car xs))
+          (loop (cons (reverse current) chunks) '() (cdr xs))]
+         [else 
+          (loop chunks (cons (car xs) current) (cdr xs))]))))
+  (map list->string chunks))
+
+
+(define (string-join strs [sep #f])
+  (apply string-append
+    (cond
+      [(empty? strs) '("")]
+      [(not sep)     strs]
+      [else          (let loop ([xs (list (car strs))] [ys (rest strs)])
+                       (if (empty? ys)
+                           (reverse xs)
+                           (loop (cons (car ys) (cons sep xs))
+                                 (cdr ys))))])))
+
+
+