diff --git a/basis/cocoa/plists/plists.factor b/basis/cocoa/plists/plists.factor
index 31b59a6eac..ceb097bb3a 100644
--- a/basis/cocoa/plists/plists.factor
+++ b/basis/cocoa/plists/plists.factor
@@ -4,7 +4,7 @@
 USING: strings arrays hashtables assocs sequences fry macros
 cocoa.messages cocoa.classes cocoa.application cocoa kernel
 namespaces io.backend math cocoa.enumeration byte-arrays
-combinators alien.c-types words core-foundation
+combinators alien.c-types words core-foundation quotations
 core-foundation.data core-foundation.utilities ;
 IN: cocoa.plists
 
@@ -41,10 +41,16 @@ DEFER: plist>
     *void* [ -> release "read-plist failed" throw ] when* ;
 
 MACRO: objc-class-case ( alist -- quot )
-    [ [ '[ dup _ execute -> isKindOfClass: c-bool> ] ] dip ] assoc-map '[ _ cond ] ;
+    [
+        dup callable?
+        [ first2 [ '[ dup _ execute -> isKindOfClass: c-bool> ] ] dip 2array ]
+        unless
+    ] map '[ _ cond ] ;
 
 PRIVATE>
 
+ERROR: invalid-plist-object object ;
+
 : plist> ( plist -- value )
     {
         { NSString [ (plist-NSString>) ] }
@@ -53,6 +59,7 @@ PRIVATE>
         { NSArray [ (plist-NSArray>) ] }
         { NSDictionary [ (plist-NSDictionary>) ] }
         { NSObject [ ] }
+        [ invalid-plist-object ]
     } objc-class-case ;
 
 : read-plist ( path -- assoc )
diff --git a/extra/game-input/iokit/iokit.factor b/extra/game-input/iokit/iokit.factor
index de1529f8df..5f09a054f9 100755
--- a/extra/game-input/iokit/iokit.factor
+++ b/extra/game-input/iokit/iokit.factor
@@ -1,13 +1,15 @@
 USING: cocoa cocoa.plists core-foundation iokit iokit.hid
 kernel cocoa.enumeration destructors math.parser cocoa.application 
 sequences locals combinators.short-circuit threads
-namespaces assocs vectors arrays combinators
+namespaces assocs vectors arrays combinators hints alien
 core-foundation.run-loop accessors sequences.private
 alien.c-types math parser game-input vectors ;
 IN: game-input.iokit
 
 SINGLETON: iokit-game-input-backend
 
+SYMBOLS: +hid-manager+ +keyboard-state+ +mouse-state+ +controller-states+ ;
+
 iokit-game-input-backend game-input-backend set-global
 
 : hid-manager-matching ( matching-seq -- alien )
@@ -23,7 +25,6 @@ iokit-game-input-backend game-input-backend set-global
 
 CONSTANT: game-devices-matching-seq
     {
-        H{ { "DeviceUsage" 1 } { "DeviceUsagePage" 1 } } ! pointers
         H{ { "DeviceUsage" 2 } { "DeviceUsagePage" 1 } } ! mouses
         H{ { "DeviceUsage" 4 } { "DeviceUsagePage" 1 } } ! joysticks
         H{ { "DeviceUsage" 5 } { "DeviceUsagePage" 1 } } ! gamepads
@@ -88,19 +89,17 @@ CONSTANT: hat-switch-matching-hash
     game-devices-matching-seq hid-manager-matching ;
 
 : device-property ( device key -- value )
-    <NSString> IOHIDDeviceGetProperty plist> ;
+    <NSString> IOHIDDeviceGetProperty [ plist> ] [ f ] if* ;
 : element-property ( element key -- value )
-    <NSString> IOHIDElementGetProperty plist> ;
+    <NSString> IOHIDElementGetProperty [ plist> ] [ f ] if* ;
 : set-element-property ( element key value -- )
     [ <NSString> ] [ >plist ] bi* IOHIDElementSetProperty drop ;
 : transfer-element-property ( element from-key to-key -- )
-    [ dupd element-property ] dip swap set-element-property ;
+    [ dupd element-property ] dip swap
+    [ set-element-property ] [ 2drop ] if* ;
 
 : mouse-device? ( device -- ? )
-    {
-        [ 1 1 IOHIDDeviceConformsTo ]
-        [ 1 2 IOHIDDeviceConformsTo ]
-    } 1|| ;
+    1 2 IOHIDDeviceConformsTo ;
 
 : controller-device? ( device -- ? )
     {
@@ -113,28 +112,31 @@ CONSTANT: hat-switch-matching-hash
     [ IOHIDElementGetUsagePage ] [ IOHIDElementGetUsage ] bi
     2array ;
 
-: button? ( {usage-page,usage} -- ? )
-    first 9 = ; inline
-: keyboard-key? ( {usage-page,usage} -- ? )
-    first 7 = ; inline
+: button? ( element -- ? )
+    IOHIDElementGetUsagePage 9 = ; inline
+: keyboard-key? ( element -- ? )
+    IOHIDElementGetUsagePage 7 = ; inline
+: axis? ( element -- ? )
+    IOHIDElementGetUsagePage 1 = ; inline
+
 : x-axis? ( {usage-page,usage} -- ? )
-    { 1 HEX: 30 } = ; inline
+    IOHIDElementGetUsage HEX: 30 = ; inline
 : y-axis? ( {usage-page,usage} -- ? )
-    { 1 HEX: 31 } = ; inline
+    IOHIDElementGetUsage HEX: 31 = ; inline
 : z-axis? ( {usage-page,usage} -- ? )
-    { 1 HEX: 32 } = ; inline
+    IOHIDElementGetUsage HEX: 32 = ; inline
 : rx-axis? ( {usage-page,usage} -- ? )
-    { 1 HEX: 33 } = ; inline
+    IOHIDElementGetUsage HEX: 33 = ; inline
 : ry-axis? ( {usage-page,usage} -- ? )
-    { 1 HEX: 34 } = ; inline
+    IOHIDElementGetUsage HEX: 34 = ; inline
 : rz-axis? ( {usage-page,usage} -- ? )
-    { 1 HEX: 35 } = ; inline
+    IOHIDElementGetUsage HEX: 35 = ; inline
 : slider? ( {usage-page,usage} -- ? )
-    { 1 HEX: 36 } = ; inline
+    IOHIDElementGetUsage HEX: 36 = ; inline
 : wheel? ( {usage-page,usage} -- ? )
-    { 1 HEX: 38 } = ; inline
+    IOHIDElementGetUsage HEX: 38 = ; inline
 : hat-switch? ( {usage-page,usage} -- ? )
-    { 1 HEX: 39 } = ; inline
+    IOHIDElementGetUsage HEX: 39 = ; inline
 
 CONSTANT: pov-values
     {
@@ -152,45 +154,55 @@ CONSTANT: pov-values
 : pov-value ( value -- pov-direction )
     IOHIDValueGetIntegerValue pov-values ?nth [ pov-neutral ] unless* ;
 
-: record-button ( hid-value usage state -- )
-    [ button-value ] [ second 1- ] [ buttons>> ] tri* set-nth ;
+: record-button ( state hid-value element -- )
+    [ buttons>> ] [ button-value ] [ IOHIDElementGetUsage 1- ] tri* rot set-nth ;
 
 : record-controller ( controller-state value -- )
-    dup IOHIDValueGetElement element-usage {
-        { [ dup button? ] [ rot record-button ] } 
-        { [ dup x-axis? ] [ drop axis-value >>x drop ] }
-        { [ dup y-axis? ] [ drop axis-value >>y drop ] }
-        { [ dup z-axis? ] [ drop axis-value >>z drop ] }
-        { [ dup rx-axis? ] [ drop axis-value >>rx drop ] }
-        { [ dup ry-axis? ] [ drop axis-value >>ry drop ] }
-        { [ dup rz-axis? ] [ drop axis-value >>rz drop ] }
-        { [ dup slider? ] [ drop axis-value >>slider drop ] }
-        { [ dup hat-switch? ] [ drop pov-value >>pov drop ] }
+    dup IOHIDValueGetElement {
+        { [ dup button? ] [ record-button ] } 
+        { [ dup axis? ] [ {
+            { [ dup x-axis? ] [ drop axis-value >>x drop ] }
+            { [ dup y-axis? ] [ drop axis-value >>y drop ] }
+            { [ dup z-axis? ] [ drop axis-value >>z drop ] }
+            { [ dup rx-axis? ] [ drop axis-value >>rx drop ] }
+            { [ dup ry-axis? ] [ drop axis-value >>ry drop ] }
+            { [ dup rz-axis? ] [ drop axis-value >>rz drop ] }
+            { [ dup slider? ] [ drop axis-value >>slider drop ] }
+            { [ dup hat-switch? ] [ drop pov-value >>pov drop ] }
+            [ 3drop ]
+        } cond ] }
         [ 3drop ]
     } cond ;
 
-SYMBOLS: +hid-manager+ +keyboard-state+ +mouse-state+ +controller-states+ ;
+HINTS: record-controller { controller-state alien } ;
 
 : ?set-nth ( value nth seq -- )
     2dup bounds-check? [ set-nth-unsafe ] [ 3drop ] if ;
 
-: record-keyboard ( value -- )
-    dup IOHIDValueGetElement element-usage keyboard-key? [
+: record-keyboard ( keyboard-state value -- )
+    dup IOHIDValueGetElement dup keyboard-key? [
         [ IOHIDValueGetIntegerValue c-bool> ]
-        [ IOHIDValueGetElement IOHIDElementGetUsage ] bi
-        +keyboard-state+ get ?set-nth
-    ] [ drop ] if ;
+        [ IOHIDElementGetUsage ] bi*
+        rot ?set-nth
+    ] [ 3drop ] if ;
 
-: record-mouse ( value -- )
-    dup IOHIDValueGetElement element-usage {
-        { [ dup button? ] [ +mouse-state+ get record-button ] }
-        { [ dup x-axis? ] [ drop mouse-axis-value +mouse-state+ get [ + ] change-dx drop ] }
-        { [ dup y-axis? ] [ drop mouse-axis-value +mouse-state+ get [ + ] change-dy drop ] }
-        { [ dup wheel?  ] [ drop mouse-axis-value +mouse-state+ get [ + ] change-scroll-dx drop ] }
-        { [ dup z-axis? ] [ drop mouse-axis-value +mouse-state+ get [ + ] change-scroll-dy drop ] }
-        [ 2drop ]
+HINTS: record-keyboard { array alien } ;
+
+: record-mouse ( mouse-state value -- )
+    dup IOHIDValueGetElement {
+        { [ dup button? ] [ record-button ] }
+        { [ dup axis? ] [ {
+            { [ dup x-axis? ] [ drop mouse-axis-value [ + ] curry change-dx drop ] }
+            { [ dup y-axis? ] [ drop mouse-axis-value [ + ] curry change-dy drop ] }
+            { [ dup wheel?  ] [ drop mouse-axis-value [ + ] curry change-scroll-dx drop ] }
+            { [ dup z-axis? ] [ drop mouse-axis-value [ + ] curry change-scroll-dy drop ] }
+            [ 3drop ]
+        } cond ] }
+        [ 3drop ]
     } cond ;
 
+HINTS: record-mouse { mouse-state alien } ;
+
 M: iokit-game-input-backend read-mouse
     +mouse-state+ get ;
 
@@ -263,8 +275,8 @@ M: iokit-game-input-backend reset-mouse
             { [ sender controller-device? ] [
                 sender +controller-states+ get at value record-controller
             ] }
-            { [ sender mouse-device? ] [ value record-mouse ] }
-            [ value record-keyboard ]
+            { [ sender mouse-device? ] [ +mouse-state+ get value record-mouse ] }
+            [ +keyboard-state+ get value record-keyboard ]
         } cond
     ] IOHIDValueCallback ;
 
@@ -289,7 +301,7 @@ M: iokit-game-input-backend (open-game-input)
     } cleave ;
 
 M: iokit-game-input-backend (reset-game-input)
-    { +hid-manager+ +keyboard-state+ +controller-states+ }
+    { +hid-manager+ +keyboard-state+ +mouse-state+ +controller-states+ }
     [ f swap set-global ] each ;
 
 M: iokit-game-input-backend (close-game-input)