diff --git a/collects/macro-debugger/model/context.ss b/collects/macro-debugger/model/context.ss
index 7ed83c0f96..c385afff38 100644
--- a/collects/macro-debugger/model/context.ss
+++ b/collects/macro-debugger/model/context.ss
@@ -6,8 +6,7 @@
          path-get
          pathseg-get
          path-replace
-         pathseg-replace
-         find-subterm-paths)
+         pathseg-replace)
 
 ;; A Path is a (list-of PathSeg)
 ;; where the PathSegs are listed outermost to innermost
@@ -117,25 +116,3 @@
 
 (define (sd x)
   (syntax->datum (datum->syntax #f x)))
-
-;;=======
-
-;; find-subterm-paths : syntax syntax -> (list-of Path)
-(define (find-subterm-paths subterm term)
-  (let outer-loop ([term term])
-    (cond [(eq? subterm term)
-           (list null)]
-          [(stx-pair? term)
-           ;; Optimized for lists...
-           (let loop ([term term] [n 0])
-             (if (stx-pair? term)
-                 (let* ([seg0 (make-ref n)])
-                   (append (map (lambda (p) (cons seg0 p)) (outer-loop (stx-car term)))
-                           (if (eq? subterm (stx-cdr term))
-                               (list (list (make-tail n)))
-                               (loop (stx-cdr term) (add1 n)))))
-                 (let ([seg0 (make-tail n)])
-                   (map (lambda (p) (cons seg0 p))
-                        (outer-loop term)))))]
-          ;; FIXME: more structured cases here: box, vector, ...
-          [else null])))
diff --git a/collects/macro-debugger/model/synth-config.ss b/collects/macro-debugger/model/synth-config.ss
deleted file mode 100644
index 2c42314301..0000000000
--- a/collects/macro-debugger/model/synth-config.ss
+++ /dev/null
@@ -1,111 +0,0 @@
-#lang scheme/base
-(require (for-syntax scheme/base)
-         scheme/match
-         scheme/contract
-         "deriv.ss"
-         "deriv-util.ss"
-         "reductions-config.ss"
-         "stx-util.ss")
-
-(provide current-unvisited-lifts
-         current-unhidden-lifts
-
-         current-hiding-warning-handler
-
-         handle-hiding-failure
-         warn
-
-         DEBUG-LIFTS
-         
-         add-unhidden-lift
-         extract/remove-unvisited-lift)
-
-;; Parameters
-
-;; current-hiding-warning-handler : (parameter-of (symbol any -> void))
-(define current-hiding-warning-handler
-  (make-parameter
-   (lambda (tag args) (printf "hiding warning: ~a\n" tag))))
-
-;; current-unvisited-lifts : (paramter-of Derivation)
-;; The derivs for the lifts yet to be seen in the processing 
-;; of the first part of the current lift-deriv.
-(define current-unvisited-lifts (make-parameter null))
-
-;; current-unhidden-lifts : (parameter-of Derivation)
-;; The derivs for those lifts that occur within unhidden macros.
-;; Derivs are moved from the current-unvisited-lifts to this list.
-(define current-unhidden-lifts (make-parameter null))
-
-;; Helper
-
-(define-syntax DEBUG-LIFTS
-  (syntax-rules ()
-    [(DEBUG-LIFTS . b)
-     (void)]
-    #;
-    [(DEBUG-LIFTS . b)
-     (begin . b)]))
-
-;; Operations
-
-;; add-unhidden-lift : Derivation -> void
-(define (add-unhidden-lift d)
-  (when d
-    (current-unhidden-lifts
-     (cons d (current-unhidden-lifts)))))
-
-;; extract/remove-unvisted-lift : identifier -> Derivation
-(define (extract/remove-unvisited-lift id)
-  (define (get-defined-id d)
-    (match d
-      [(Wrap deriv (e1 e2))
-       (with-syntax ([(?define-values (?id) ?expr) e1])
-         #'?id)]))
-  ;; The Wrong Way
-  (let ([unvisited (current-unvisited-lifts)])
-    (if (null? unvisited)
-        (begin (DEBUG-LIFTS
-                (printf "hide:extract/remove-unvisited-lift: out of lifts!"))
-               #f)
-        (let ([lift (car unvisited)])
-          (DEBUG-LIFTS
-           (printf "extracting lift: ~s left\n" (length (cdr unvisited))))
-          (current-unvisited-lifts (cdr unvisited))
-          lift)))
-  ;; The Right Way
-  ;; FIXME: Doesn't work inside of modules. Why not?
-  #;
-  (let loop ([lifts (current-unvisited-lifts)]
-             [prefix null])
-    (cond [(null? lifts)
-           (DEBUG-LIFTS
-            (fprintf (current-error-port)
-                     "hide:extract/remove-unvisited-lift: can't find lift for ~s~n"
-                     id))
-           (raise (make localactions))]
-          [(bound-identifier=? id (get-defined-id (car lifts)))
-           (let ([lift (car lifts)])
-             (current-unvisited-lifts
-              (let loop ([prefix prefix] [lifts (cdr lifts)])
-                (if (null? prefix)
-                    lifts
-                    (loop (cdr prefix) (cons (car prefix) lifts)))))
-             lift)]
-          [else
-           (loop (cdr lifts) (cons (car lifts) prefix))])))
-
-;; Warnings
-
-(define (warn tag . args)
-  ((current-hiding-warning-handler) tag args))
-
-(define (handle-hiding-failure d failure)
-  (match failure
-    [(struct nonlinearity (term paths))
-     (warn 'nonlinearity term paths d)]
-    [(struct localactions ())
-     (warn 'localactions d)]
-    [(struct hidden-lift-site ())
-     (warn 'hidden-lift-site d)]))
-
diff --git a/collects/macro-debugger/syntax-browser/controller.ss b/collects/macro-debugger/syntax-browser/controller.ss
index 030c9389d1..e1a1da87e5 100644
--- a/collects/macro-debugger/syntax-browser/controller.ss
+++ b/collects/macro-debugger/syntax-browser/controller.ss
@@ -1,10 +1,11 @@
-
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:]
+                    [init-field/i init-field:])
          "interfaces.ss"
          "partition.ss"
-         "../util/notify.ss")
+         unstable/gui/notify)
 (provide controller%)
 
 ;; displays-manager-mixin
diff --git a/collects/macro-debugger/syntax-browser/display.ss b/collects/macro-debugger/syntax-browser/display.ss
index 9fe40f88ca..2de3c18e93 100644
--- a/collects/macro-debugger/syntax-browser/display.ss
+++ b/collects/macro-debugger/syntax-browser/display.ss
@@ -2,7 +2,9 @@
 (require scheme/class
          scheme/gui
          scheme/list
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:]
+                    [init-field/i init-field:])
          (only-in mzlib/etc begin-with-definitions)
          "pretty-printer.ss"
          "interfaces.ss"
diff --git a/collects/macro-debugger/syntax-browser/frame.ss b/collects/macro-debugger/syntax-browser/frame.ss
index 9f41e052c3..7b4a3fffcf 100644
--- a/collects/macro-debugger/syntax-browser/frame.ss
+++ b/collects/macro-debugger/syntax-browser/frame.ss
@@ -1,6 +1,10 @@
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [define/i define:]
+                    [send/i send:]
+                    [send*/i send*:]
+                    [init-field/i init-field:])
          scheme/gui
          framework/framework
          scheme/list
diff --git a/collects/macro-debugger/syntax-browser/interfaces.ss b/collects/macro-debugger/syntax-browser/interfaces.ss
index 4f71cb542e..5b72ce7eb5 100644
--- a/collects/macro-debugger/syntax-browser/interfaces.ss
+++ b/collects/macro-debugger/syntax-browser/interfaces.ss
@@ -1,6 +1,6 @@
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         unstable/class-iop
          (for-syntax scheme/base))
 (provide (all-defined-out))
 
diff --git a/collects/macro-debugger/syntax-browser/keymap.ss b/collects/macro-debugger/syntax-browser/keymap.ss
index 7bc7c8fd17..10dad67c8f 100644
--- a/collects/macro-debugger/syntax-browser/keymap.ss
+++ b/collects/macro-debugger/syntax-browser/keymap.ss
@@ -1,7 +1,7 @@
 #lang scheme/base
 (require scheme/class
          scheme/gui
-         "../util/notify.ss"
+         unstable/gui/notify
          "interfaces.ss"
          "partition.ss")
 (provide smart-keymap%
diff --git a/collects/macro-debugger/syntax-browser/prefs.ss b/collects/macro-debugger/syntax-browser/prefs.ss
index fe86c83f47..ca3d7723c7 100644
--- a/collects/macro-debugger/syntax-browser/prefs.ss
+++ b/collects/macro-debugger/syntax-browser/prefs.ss
@@ -3,8 +3,8 @@
 (require scheme/class
          framework/framework
          "interfaces.ss"
-         "../util/notify.ss"
-         "../util/misc.ss")
+         unstable/gui/notify
+         unstable/gui/prefs)
 (provide prefs-base%
          syntax-prefs-base%
          syntax-prefs%
diff --git a/collects/macro-debugger/syntax-browser/pretty-helper.ss b/collects/macro-debugger/syntax-browser/pretty-helper.ss
index cf5e265a8b..73b22466e9 100644
--- a/collects/macro-debugger/syntax-browser/pretty-helper.ss
+++ b/collects/macro-debugger/syntax-browser/pretty-helper.ss
@@ -1,8 +1,8 @@
-
 #lang scheme/base
 (require scheme/class
          scheme/pretty
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:])
          syntax/stx
          unstable/struct
          "interfaces.ss")
diff --git a/collects/macro-debugger/syntax-browser/properties.ss b/collects/macro-debugger/syntax-browser/properties.ss
index 63176ba9c2..f6a1a9d70a 100644
--- a/collects/macro-debugger/syntax-browser/properties.ss
+++ b/collects/macro-debugger/syntax-browser/properties.ss
@@ -1,8 +1,8 @@
-
 #lang scheme/base
 (require scheme/class
          scheme/gui
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:])
          "interfaces.ss"
          "util.ss"
          "../util/mpi.ss")
diff --git a/collects/macro-debugger/syntax-browser/syntax-snip.ss b/collects/macro-debugger/syntax-browser/syntax-snip.ss
index d002b16507..7aeba5139d 100644
--- a/collects/macro-debugger/syntax-browser/syntax-snip.ss
+++ b/collects/macro-debugger/syntax-browser/syntax-snip.ss
@@ -1,13 +1,13 @@
-
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:])
          scheme/match
          scheme/list
          mzlib/string
          mred
          framework
-         "../util/notify.ss"
+         unstable/gui/notify
          "interfaces.ss"
          "display.ss"
          "controller.ss"
diff --git a/collects/macro-debugger/syntax-browser/text.ss b/collects/macro-debugger/syntax-browser/text.ss
index b6f30f1cc2..72193dc326 100644
--- a/collects/macro-debugger/syntax-browser/text.ss
+++ b/collects/macro-debugger/syntax-browser/text.ss
@@ -5,7 +5,7 @@
          scheme/gui
          drscheme/arrow
          framework/framework
-         "../util/notify.ss")
+         unstable/gui/notify)
 
 (provide text:hover<%>
          text:hover-identifier<%>
diff --git a/collects/macro-debugger/syntax-browser/widget.ss b/collects/macro-debugger/syntax-browser/widget.ss
index f32e001206..7685f8f6a4 100644
--- a/collects/macro-debugger/syntax-browser/widget.ss
+++ b/collects/macro-debugger/syntax-browser/widget.ss
@@ -1,4 +1,3 @@
-
 #lang scheme/base
 (require scheme/class
          mred
@@ -6,7 +5,8 @@
          scheme/list
          scheme/match
          syntax/id-table
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:])
          "interfaces.ss"
          "controller.ss"
          "display.ss"
diff --git a/collects/macro-debugger/util/misc.ss b/collects/macro-debugger/util/misc.ss
deleted file mode 100644
index 4790f20a21..0000000000
--- a/collects/macro-debugger/util/misc.ss
+++ /dev/null
@@ -1,25 +0,0 @@
-
-#lang scheme/base
-(require (for-syntax scheme/base)
-         scheme/class
-         framework/framework)
-(provide closure-mixin
-         pref:get/set)
-
-(define-syntax pref:get/set
-  (syntax-rules ()
-    [(_ get/set prop)
-     (define get/set
-       (case-lambda
-         [() (preferences:get 'prop)]
-         [(newval) (preferences:set 'prop newval)]))]))
-
-(define-syntax (closure-mixin stx)
-  (syntax-case stx ()
-    [(closure-mixin interfaces [name proc] ...)
-     (with-syntax ([(iname ...) (generate-temporaries #'(name ...))])
-       #'(let ([iname proc] ...)
-           (mixin () interfaces
-             (define/public (name . args) (apply iname args))
-             ...
-             (super-new))))]))
diff --git a/collects/macro-debugger/view/debug.ss b/collects/macro-debugger/view/debug.ss
index 1b12f0f7ab..dff2ec1061 100644
--- a/collects/macro-debugger/view/debug.ss
+++ b/collects/macro-debugger/view/debug.ss
@@ -1,8 +1,8 @@
-
 #lang scheme/base
 (require scheme/pretty
          scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:])
          "interfaces.ss"
          "debug-format.ss"
          "prefs.ss"
diff --git a/collects/macro-debugger/view/extensions.ss b/collects/macro-debugger/view/extensions.ss
index 64a8779b58..1894f8074a 100644
--- a/collects/macro-debugger/view/extensions.ss
+++ b/collects/macro-debugger/view/extensions.ss
@@ -1,7 +1,9 @@
-
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:]
+                    [send*/i send*:]
+                    [init-field/i init-field:])
          scheme/unit
          scheme/list
          scheme/match
@@ -20,7 +22,7 @@
          "../model/trace.ss"
          "../model/steps.ss"
          "cursor.ss"
-         "../util/notify.ss")
+         unstable/gui/notify)
 (provide stepper-keymap%
          stepper-syntax-widget%)
 
diff --git a/collects/macro-debugger/view/frame.ss b/collects/macro-debugger/view/frame.ss
index 9c5eb54f9b..301bcf4727 100644
--- a/collects/macro-debugger/view/frame.ss
+++ b/collects/macro-debugger/view/frame.ss
@@ -1,7 +1,8 @@
-
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [define/i define:]
+                    [send/i send:])
          scheme/unit
          scheme/list
          scheme/file
@@ -21,7 +22,7 @@
          "../model/trace.ss"
          "../model/steps.ss"
          "cursor.ss"
-         "../util/notify.ss")
+         unstable/gui/notify)
 (provide macro-stepper-frame-mixin)
 
 (define (macro-stepper-frame-mixin base-frame%)
diff --git a/collects/macro-debugger/view/hiding-panel.ss b/collects/macro-debugger/view/hiding-panel.ss
index be6b24890b..6522fcd23b 100644
--- a/collects/macro-debugger/view/hiding-panel.ss
+++ b/collects/macro-debugger/view/hiding-panel.ss
@@ -1,14 +1,15 @@
-
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:]
+                    [init-field/i init-field:])
          scheme/gui
          scheme/list
          syntax/boundmap
          "interfaces.ss"
          "../model/hiding-policies.ss"
          "../util/mpi.ss"
-         "../util/notify.ss")
+         unstable/gui/notify)
 (provide macro-hiding-prefs-widget%)
 
 (define mode:disable "Disable")
diff --git a/collects/macro-debugger/view/interfaces.ss b/collects/macro-debugger/view/interfaces.ss
index 4c7ddae67f..747c930cf8 100644
--- a/collects/macro-debugger/view/interfaces.ss
+++ b/collects/macro-debugger/view/interfaces.ss
@@ -1,6 +1,5 @@
-
 #lang scheme/base
-(require macro-debugger/util/class-iop
+(require unstable/class-iop
          (prefix-in sb: "../syntax-browser/interfaces.ss"))
 (provide (all-defined-out))
 
diff --git a/collects/macro-debugger/view/prefs.ss b/collects/macro-debugger/view/prefs.ss
index 2986b1931c..5dd1bf0d74 100644
--- a/collects/macro-debugger/view/prefs.ss
+++ b/collects/macro-debugger/view/prefs.ss
@@ -4,8 +4,8 @@
          framework/framework
          "interfaces.ss"
          "../syntax-browser/prefs.ss"
-         "../util/notify.ss"
-         "../util/misc.ss")
+         unstable/gui/notify
+         unstable/gui/prefs)
 (provide pref:macro-step-limit
          macro-stepper-config-base%
          macro-stepper-config/prefs%
diff --git a/collects/macro-debugger/view/step-display.ss b/collects/macro-debugger/view/step-display.ss
index 5a9196a942..65be319aa7 100644
--- a/collects/macro-debugger/view/step-display.ss
+++ b/collects/macro-debugger/view/step-display.ss
@@ -1,7 +1,9 @@
-
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:]
+                    [send*/i send*:]
+                    [init-field/i init-field:])
          scheme/unit
          scheme/list
          scheme/match
@@ -20,7 +22,7 @@
          "../model/reductions-config.ss"
          "../model/reductions.ss"
          "../model/steps.ss"
-         "../util/notify.ss"
+         unstable/gui/notify
 	 (prefix-in sb: "../syntax-browser/interfaces.ss")
          "cursor.ss"
          "debug-format.ss")
diff --git a/collects/macro-debugger/view/stepper.ss b/collects/macro-debugger/view/stepper.ss
index ccc89924c3..ecab49d28f 100644
--- a/collects/macro-debugger/view/stepper.ss
+++ b/collects/macro-debugger/view/stepper.ss
@@ -1,7 +1,10 @@
-
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [define/i define:]
+                    [send/i send:]
+                    [send*/i send*:]
+                    [init-field/i init-field:])
          scheme/unit
          scheme/list
          scheme/match
@@ -22,7 +25,7 @@
          "../model/reductions.ss"
          "../model/steps.ss"
          "cursor.ss"
-         "../util/notify.ss"
+         unstable/gui/notify
          (only-in mzscheme [#%top-interaction mz-top-interaction]))
 (provide macro-stepper-widget%
          macro-stepper-widget/process-mixin)
diff --git a/collects/macro-debugger/view/term-record.ss b/collects/macro-debugger/view/term-record.ss
index 2fc563725e..fe404adf75 100644
--- a/collects/macro-debugger/view/term-record.ss
+++ b/collects/macro-debugger/view/term-record.ss
@@ -1,6 +1,9 @@
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [define/i define:]
+                    [send/i send:]
+                    [init-field/i init-field:])
          scheme/unit
          scheme/list
          scheme/match
@@ -22,7 +25,7 @@
          "../model/reductions-config.ss"
          "../model/reductions.ss"
          "../model/steps.ss"
-         "../util/notify.ss"
+         unstable/gui/notify
          "cursor.ss"
          "debug-format.ss")
 
diff --git a/collects/macro-debugger/view/view.ss b/collects/macro-debugger/view/view.ss
index 3d831bdee4..7162a983a6 100644
--- a/collects/macro-debugger/view/view.ss
+++ b/collects/macro-debugger/view/view.ss
@@ -1,7 +1,7 @@
-
 #lang scheme/base
 (require scheme/class
-         macro-debugger/util/class-iop
+         (rename-in unstable/class-iop
+                    [send/i send:])
          scheme/pretty
          scheme/gui
          framework/framework
diff --git a/collects/macro-debugger/util/class-iop.ss b/collects/unstable/class-iop.ss
similarity index 90%
rename from collects/macro-debugger/util/class-iop.ss
rename to collects/unstable/class-iop.ss
index ae89b2fa39..a6a07e3279 100644
--- a/collects/macro-debugger/util/class-iop.ss
+++ b/collects/unstable/class-iop.ss
@@ -3,20 +3,21 @@
          (for-syntax scheme/base
                      syntax/parse
                      unstable/syntax
-                     "class-ct.ss"))
+                     "private/class-iop-ct.ss"))
 (provide define-interface
          define-interface/dynamic
          define-interface-expander
 
-         send:
-         send*:
-         send/apply:
+         (rename-out [send: send/i]
+                     [send*: send*/i]
+                     [send/apply: send/apply/i]
 
-         define:
-         lambda:
-         init:
-	 init-field:
-         init-private:)
+                     [define: define/i]
+                     #| lambda: |#
+
+                     [init: init/i]
+                     [init-field: init-field/i]
+                     [init-private: init-private/i]))
 
 ;; Configuration
 (define-for-syntax warn-on-dynamic-interfaces? #f)
@@ -65,7 +66,7 @@
 (begin-for-syntax
   (define (check-method-in-interface for-whom method si)
     (unless (member (syntax-e method) (static-interface-members si))
-      (raise-syntax-error for-whom
+      (raise-syntax-error (syntax-e for-whom)
                           "method not in static interface"
                           method))))
 
@@ -74,7 +75,7 @@
 (define-syntax (send: stx)
   (syntax-parse stx
     [(send: obj:expr iface:static-interface method:id . args)
-     (begin (check-method-in-interface 'send: #'method (attribute iface.value))
+     (begin (check-method-in-interface #'send: #'method (attribute iface.value))
             (syntax/loc stx
               (send (check-object<:interface send: obj iface)
                     method . args)))]))
@@ -83,7 +84,7 @@
   (syntax-parse stx
     [(send*: obj:expr iface:static-interface (method:id . args) ...)
      (begin (for ([method (syntax->list #'(method ...))])
-              (check-method-in-interface 'send*: method (attribute iface.value)))
+              (check-method-in-interface #'send*: method (attribute iface.value)))
             (syntax/loc stx 
               (send* (check-object<:interface send*: obj iface)
                 (method . args) ...)))]))
@@ -91,9 +92,9 @@
 (define-syntax (send/apply: stx)
   (syntax-parse stx
     [(send/apply: obj:expr iface:static-interface method:id . args)
-     (begin (check-method-in-interface 'send/apply: #'method (attribute iface.value))
+     (begin (check-method-in-interface #'send/apply: #'method (attribute iface.value))
             (syntax/loc stx 
-              (send/apply (check-object<:interface send/apply obj iface)
+              (send/apply (check-object<:interface send/apply: obj iface)
                           method . args)))]))
 
 ;;
diff --git a/collects/macro-debugger/util/notify.ss b/collects/unstable/gui/notify.ss
similarity index 99%
rename from collects/macro-debugger/util/notify.ss
rename to collects/unstable/gui/notify.ss
index 2eb7d9c57c..b73efc59e3 100644
--- a/collects/macro-debugger/util/notify.ss
+++ b/collects/unstable/gui/notify.ss
@@ -3,7 +3,6 @@
 (require (for-syntax scheme/base unstable/syntax)
          scheme/list
          scheme/class
-         macro-debugger/util/class-iop
          scheme/gui)
 (provide define/listen
          field/notify
diff --git a/collects/unstable/gui/prefs.ss b/collects/unstable/gui/prefs.ss
new file mode 100644
index 0000000000..ebc5aa07f3
--- /dev/null
+++ b/collects/unstable/gui/prefs.ss
@@ -0,0 +1,13 @@
+
+#lang scheme/base
+(require (for-syntax scheme/base)
+         framework/framework)
+(provide pref:get/set)
+
+(define-syntax pref:get/set
+  (syntax-rules ()
+    [(_ get/set prop)
+     (define get/set
+       (case-lambda
+         [() (preferences:get 'prop)]
+         [(newval) (preferences:set 'prop newval)]))]))
diff --git a/collects/macro-debugger/util/class-ct.ss b/collects/unstable/private/class-iop-ct.ss
similarity index 100%
rename from collects/macro-debugger/util/class-ct.ss
rename to collects/unstable/private/class-iop-ct.ss
diff --git a/collects/unstable/scribblings/class-iop.scrbl b/collects/unstable/scribblings/class-iop.scrbl
new file mode 100644
index 0000000000..93ce21ecb1
--- /dev/null
+++ b/collects/unstable/scribblings/class-iop.scrbl
@@ -0,0 +1,125 @@
+#lang scribble/manual
+@(require scribble/eval
+          (for-label unstable/class-iop
+                     scheme/class
+                     scheme/contract
+                     scheme/base))
+
+@title[#:tag "class-iop"]{Interface-Oriented Programming for Classes}
+
+@(define the-eval (make-base-eval))
+@(the-eval '(require scheme/class unstable/class-iop))
+
+@defmodule[unstable/class-iop]
+
+@defform[(define-interface name-id (super-ifc-id ...) (method-id ...))]{
+
+Defines @scheme[name-id] as a static interface extending the
+interfaces named by the @scheme[super-ifc-id]s and containing the
+methods specified by the @scheme[method-id]s.
+
+A static interface name is used by the checked method call variants
+(@scheme[send/i], @scheme[send*/i], and @scheme[send/apply/i]). When
+used as an expression, a static interface name evaluates to an
+interface value.
+
+@examples[#:eval the-eval
+(define-interface stack<%> () (empty? push pop))
+stack<%>
+(define stack%
+  (class* object% (stack<%>)
+    (define items null)
+    (define/public (empty?) (null? items))
+    (define/public (push x) (set! items (cons x items)))
+    (define/public (pop) (begin (car items) (set! items (cdr items))))
+    (super-new)))
+]
+}
+
+@defform[(define-interface/dynamic name-id ifc-expr (method-id ...))]{
+
+Defines @scheme[name-id] as a static interface with dynamic
+counterpart @scheme[ifc-expr], which must evaluate to an interface
+value. The static interface contains the methods named by the
+@scheme[method-id]s. A run-time error is raised if any
+@scheme[method-id] is not a member of the dynamic interface
+@scheme[ifc-expr].
+
+Use @scheme[define-interface/dynamic] to wrap interfaces from other
+sources.
+
+@examples[#:eval the-eval
+(define-interface/dynamic object<%> (class->interface object%) ())
+object<%>
+]
+}
+
+@defform[(send/i obj-exp static-ifc-id method-id arg-expr ...)]{
+
+Checked variant of @scheme[send]. 
+
+The argument @scheme[static-ifc-id] must be defined as a static
+interface. The method @scheme[method-id] must be a member of the
+static interface @scheme[static-ifc-id]; otherwise a compile-time
+error is raised.
+
+The value of @scheme[obj-expr] must be an instance of the interface
+@scheme[static-ifc-id]; otherwise, a run-time error is raised.
+
+@examples[#:eval the-eval
+(define s (new stack%))
+(send/i s stack<%> push 1)
+(send/i s stack<%> popp)
+(send/i (new object%) stack<%> push 2)
+]
+}
+
+@defform[(send*/i obj-expr static-ifc-id (method-id arg-expr ...) ...)]{
+
+Checked variant of @scheme[send*].
+
+@examples[#:eval the-eval
+(send*/i s stack<%>
+  (push 2)
+  (pop))
+]
+}
+
+@defform[(send/apply/i obj-expr static-ifc-id method-id arg-expr ... list-arg-expr)]{
+
+Checked variant of @scheme[send/apply].
+
+@examples[#:eval the-eval
+(send/apply/i s stack<%> push (list 5))
+]
+}
+
+@defform[(define/i id static-ifc-id expr)]{
+
+Checks that @scheme[expr] evaluates to an instance of
+@scheme[static-ifc-id] before binding it to @scheme[id]. If
+@scheme[id] is subsequently changed (with @scheme[set!]), the check is
+performed again.
+
+No dynamic object check is performed when calling a method (using
+@scheme[send/i], etc) on a name defined via @scheme[define/i].
+
+}
+
+@deftogether[[
+@defform[(init/i (id static-ifc-id maybe-default-expr) ...)]
+@defform[(init-field/i (id static-ifc-id maybe-default-expr) ...)]
+@defform/subs[(init-private/i (id static-ifc-id maybe-default-expr) ...)
+              ([maybe-default-expr (code:blank)
+                                   default-expr])]]]{
+
+Checked versions of @scheme[init] and @scheme[init-field]. The value
+attached to each @scheme[id] is checked against the given interface.
+
+No dynamic object check is performed when calling a method (using
+@scheme[send/i], etc) on a name bound via one of these forms.  Note
+that in the case of @scheme[init-field/i] this check omission is
+unsound in the presence of mutation from outside the class. This
+should be fixed.
+
+}
diff --git a/collects/unstable/scribblings/find.scrbl b/collects/unstable/scribblings/find.scrbl
index b82de303c1..36ce5d2cbe 100644
--- a/collects/unstable/scribblings/find.scrbl
+++ b/collects/unstable/scribblings/find.scrbl
@@ -60,7 +60,7 @@ mutable table.
                      [#:default default any/c (lambda () (error ....))])
          any/c]{
 
-Like @scheme[find-first], but only returns the first match. If no
+Like @scheme[find], but only returns the first match. If no
 matches are found, @scheme[default] is applied as a thunk if it is a
 procedure or returned otherwise.
 
diff --git a/collects/unstable/scribblings/unstable.scrbl b/collects/unstable/scribblings/unstable.scrbl
index 13e2d892b0..3dde2e3c66 100644
--- a/collects/unstable/scribblings/unstable.scrbl
+++ b/collects/unstable/scribblings/unstable.scrbl
@@ -83,6 +83,7 @@ Keep documentation and tests up to date.
 @include-section["poly-c.scrbl"]
 @include-section["mutated-vars.scrbl"]
 @include-section["find.scrbl"]
+@include-section["class-iop.scrbl"]
 
 @;{--------}
 
diff --git a/collects/unstable/struct.ss b/collects/unstable/struct.ss
index dde3f1fc4a..1384d643fb 100644
--- a/collects/unstable/struct.ss
+++ b/collects/unstable/struct.ss
@@ -49,7 +49,7 @@
 (define dummy-value (box 'dummy))
 
 ;; struct->list : struct?
-;;                #:on-opaque? (or/c 'error 'return-false 'skip)
+;;                #:on-opaque (or/c 'error 'return-false 'skip)
 ;;             -> (listof any/c)
 (define (struct->list s
                       #:on-opaque [on-opaque 'error])