diff --git a/extra/peg/peg.factor b/extra/peg/peg.factor
index 00271a9ad3..dd0b11fce3 100755
--- a/extra/peg/peg.factor
+++ b/extra/peg/peg.factor
@@ -3,7 +3,8 @@
 USING: kernel sequences strings namespaces math assocs shuffle 
        vectors arrays combinators.lib math.parser match
        unicode.categories sequences.lib compiler.units parser
-       words quotations effects memoize accessors combinators.cleave ;
+       words quotations effects memoize accessors 
+       combinators.cleave locals ;
 IN: peg
 
 TUPLE: parse-result remaining ast ;
@@ -14,9 +15,23 @@ SYMBOL: ignore
   parse-result construct-boa ;
 
 SYMBOL: compiled-parsers
+SYMBOL: packrat
+SYMBOL: failed
 
 GENERIC: (compile) ( parser -- quot )
 
+:: run-packrat-parser ( input quot c -- result )
+  input slice? [ input slice-from ] [ 0 ] if
+  quot c [ drop H{ } clone ] cache 
+  [
+    drop input quot call  
+  ] cache ; inline
+
+: run-parser ( input quot -- result )
+  #! If a packrat cache is available, use memoization for
+  #! packrat parsing, otherwise do a standard peg call.
+  packrat get [ run-packrat-parser ] [ call ] if* ; inline
+
 : compiled-parser ( parser -- word )
   #! Look to see if the given parser has been compiled.
   #! If not, compile it to a temporary word, cache it,
@@ -24,11 +39,11 @@ GENERIC: (compile) ( parser -- quot )
   dup compiled-parsers get at [
     nip
   ] [
-    dup (compile) define-temp 
+    dup (compile) [ run-parser ] curry define-temp 
     [ swap compiled-parsers get set-at ] keep
   ] if* ;
 
-MEMO: compile ( parser -- word )
+: compile ( parser -- word )
   H{ } clone compiled-parsers [ 
     [ compiled-parser ] with-compilation-unit 
   ] with-variable ;
diff --git a/extra/ui/gadgets/scrollers/scrollers.factor b/extra/ui/gadgets/scrollers/scrollers.factor
index 98951b74e3..7966f4e206 100755
--- a/extra/ui/gadgets/scrollers/scrollers.factor
+++ b/extra/ui/gadgets/scrollers/scrollers.factor
@@ -3,13 +3,14 @@
 USING: arrays ui.gadgets
 ui.gadgets.viewports ui.gadgets.frames ui.gadgets.grids
 ui.gadgets.theme ui.gadgets.sliders ui.gestures kernel math
-namespaces sequences models combinators math.vectors ;
+namespaces sequences models combinators math.vectors
+tuples ;
 IN: ui.gadgets.scrollers
 
 TUPLE: scroller viewport x y follows ;
 
 : find-scroller ( gadget -- scroller/f )
-    [ scroller? ] find-parent ;
+    [ [ scroller? ] is? ] find-parent ;
 
 : scroll-up-page scroller-y -1 swap slide-by-page ;
 
diff --git a/extra/ui/tools/listener/listener.factor b/extra/ui/tools/listener/listener.factor
index 75401b3861..7db0d63f45 100755
--- a/extra/ui/tools/listener/listener.factor
+++ b/extra/ui/tools/listener/listener.factor
@@ -6,7 +6,8 @@ kernel models namespaces parser quotations sequences ui.commands
 ui.gadgets ui.gadgets.editors ui.gadgets.labelled
 ui.gadgets.panes ui.gadgets.buttons ui.gadgets.scrollers
 ui.gadgets.tracks ui.gestures ui.operations vocabs words
-prettyprint listener debugger threads boxes concurrency.flags ;
+prettyprint listener debugger threads boxes concurrency.flags
+math arrays ;
 IN: ui.tools.listener
 
 TUPLE: listener-gadget input output stack ;
@@ -23,9 +24,19 @@ TUPLE: listener-gadget input output stack ;
 : <listener-input> ( listener -- gadget )
     listener-gadget-output <pane-stream> <interactor> ;
 
+TUPLE: input-scroller ;
+
+: <input-scroller> ( interactor -- scroller )
+    <scroller>
+    input-scroller construct-empty
+    [ set-gadget-delegate ] keep ;
+
+M: input-scroller pref-dim*
+    drop { 0 100 } ;
+
 : listener-input, ( -- )
     g <listener-input> g-> set-listener-gadget-input
-    <scroller> "Input" <labelled-gadget> f track, ;
+    <input-scroller> "Input" <labelled-gadget> f track, ;
 
 : welcome. ( -- )
    "If this is your first time with Factor, please read the " print