diff --git a/.hg_archival.txt b/.hg_archival.txt
new file mode 100644
--- /dev/null
+++ b/.hg_archival.txt
@@ -0,0 +1,2 @@
+repo: 73f9f23123106e581edbcf74b725d9a23e2eb1f4
+node: 7eab16509ef9e1c66dac522e1cfb48701d3ee1e8
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,5 @@
+#!/usr/bin/env runhaskell
+
+import Distribution.Simple
+
+main = defaultMain
diff --git a/gtk2hs-rpn.cabal b/gtk2hs-rpn.cabal
new file mode 100644
--- /dev/null
+++ b/gtk2hs-rpn.cabal
@@ -0,0 +1,29 @@
+cabal-Version: >= 1.2
+name: gtk2hs-rpn
+version: 0.0.1
+synopsis:
+  Adds a module to gtk2hs allowing layouts to
+  be defined using reverse polish notation.
+description:
+  Adds a module 'Graphics.UI.Gtk.Layout.Rpn' to
+  gtk2hs. This module defines a type 'RPN' for
+  operators, and is an instance of Monoid class.
+  You can combine those operators to define a
+  layout, as well as buttons and other widgets.
+build-type: Simple
+license: LGPL
+maintainer: Maurício CA <mauricio.antunes@gmail.com>
+category: GUI
+Library
+  build-depends: base, gtk >= 0.10, cairo, mtl
+  hs-source-dirs: src
+  extensions:
+    NoMonomorphismRestriction
+  exposed-modules:
+    Graphics.UI.Gtk.Layout.Rpn
+Executable example
+  main-is: example.hs
+  build-depends: base, gtk >= 0.10, cairo
+  hs-source-dirs: src
+  extensions:
+    NoMonomorphismRestriction
diff --git a/src/CanBeCasted.hs b/src/CanBeCasted.hs
new file mode 100644
--- /dev/null
+++ b/src/CanBeCasted.hs
@@ -0,0 +1,508 @@
+module CanBeCasted where {
+import Graphics.UI.Gtk ;
+import Graphics.UI.Gtk.Types ;
+
+ class ( GObjectClass g ) => CanBeCasted g where {
+     glibCast :: ( GObjectClass o ) => o -> Maybe g ;
+     glibCast a = if isA a t then Just ( c a ) else Nothing
+         where { ( t , c ) = castData } ;
+     castData :: ( GObjectClass g1 ) => ( GType , g1 -> g )
+ } ;
+
+ instance CanBeCasted AboutDialog where {
+     castData = ( gTypeAboutDialog , castToAboutDialog )
+ } ;
+ instance CanBeCasted AccelLabel where {
+     castData = ( gTypeAccelLabel , castToAccelLabel )
+ } ;
+ instance CanBeCasted Action where {
+     castData = ( gTypeAction , castToAction )
+ } ;
+ instance CanBeCasted ActionGroup where {
+     castData = ( gTypeActionGroup , castToActionGroup )
+ } ;
+-- instance CanBeCasted Adapter where {
+--     castData = ( gTypeAdapter , castToAdapter )
+-- } ;
+ instance CanBeCasted Adjustment where {
+     castData = ( gTypeAdjustment , castToAdjustment )
+ } ;
+ instance CanBeCasted Alignment where {
+     castData = ( gTypeAlignment , castToAlignment )
+ } ;
+ instance CanBeCasted Arrow where {
+     castData = ( gTypeArrow , castToArrow )
+ } ;
+ instance CanBeCasted AspectFrame where {
+     castData = ( gTypeAspectFrame , castToAspectFrame )
+ } ;
+-- instance CanBeCasted BaseSink where {
+--     castData = ( gTypeBaseSink , castToBaseSink )
+-- } ;
+-- instance CanBeCasted BaseSrc where {
+--     castData = ( gTypeBaseSrc , castToBaseSrc )
+-- } ;
+-- instance CanBeCasted BaseTransform where {
+--     castData = ( gTypeBaseTransform , castToBaseTransform )
+-- } ;
+ instance CanBeCasted Bin where {
+     castData = ( gTypeBin , castToBin )
+ } ;
+ instance CanBeCasted Box where {
+     castData = ( gTypeBox , castToBox )
+ } ;
+-- instance CanBeCasted Buffer where {
+--     castData = ( gTypeBuffer , castToBuffer )
+-- } ;
+-- instance CanBeCasted Bus where {
+--     castData = ( gTypeBus , castToBus )
+-- } ;
+ instance CanBeCasted Button where {
+     castData = ( gTypeButton , castToButton )
+ } ;
+ instance CanBeCasted ButtonBox where {
+     castData = ( gTypeButtonBox , castToButtonBox )
+ } ;
+ instance CanBeCasted Calendar where {
+     castData = ( gTypeCalendar , castToCalendar )
+ } ;
+ instance CanBeCasted CellRenderer where {
+     castData = ( gTypeCellRenderer , castToCellRenderer )
+ } ;
+ instance CanBeCasted CellRendererCombo where {
+     castData = ( gTypeCellRendererCombo , castToCellRendererCombo )
+ } ;
+ instance CanBeCasted CellRendererPixbuf where {
+     castData = ( gTypeCellRendererPixbuf , castToCellRendererPixbuf )
+ } ;
+ instance CanBeCasted CellRendererProgress where {
+     castData = ( gTypeCellRendererProgress , castToCellRendererProgress )
+ } ;
+ instance CanBeCasted CellRendererText where {
+     castData = ( gTypeCellRendererText , castToCellRendererText )
+ } ;
+ instance CanBeCasted CellRendererToggle where {
+     castData = ( gTypeCellRendererToggle , castToCellRendererToggle )
+ } ;
+ instance CanBeCasted CellView where {
+     castData = ( gTypeCellView , castToCellView )
+ } ;
+ instance CanBeCasted CheckButton where {
+     castData = ( gTypeCheckButton , castToCheckButton )
+ } ;
+ instance CanBeCasted CheckMenuItem where {
+     castData = ( gTypeCheckMenuItem , castToCheckMenuItem )
+ } ;
+ instance CanBeCasted Clipboard where {
+     castData = ( gTypeClipboard , castToClipboard )
+ } ;
+-- instance CanBeCasted Clock where {
+--     castData = ( gTypeClock , castToClock )
+-- } ;
+ instance CanBeCasted ColorButton where {
+     castData = ( gTypeColorButton , castToColorButton )
+ } ;
+ instance CanBeCasted ColorSelection where {
+     castData = ( gTypeColorSelection , castToColorSelection )
+ } ;
+ instance CanBeCasted ColorSelectionDialog where {
+     castData = ( gTypeColorSelectionDialog , castToColorSelectionDialog )
+ } ;
+ instance CanBeCasted Combo where {
+     castData = ( gTypeCombo , castToCombo )
+ } ;
+ instance CanBeCasted ComboBox where {
+     castData = ( gTypeComboBox , castToComboBox )
+ } ;
+ instance CanBeCasted ComboBoxEntry where {
+     castData = ( gTypeComboBoxEntry , castToComboBoxEntry )
+ } ;
+ instance CanBeCasted Container where {
+     castData = ( gTypeContainer , castToContainer )
+ } ;
+ instance CanBeCasted Dialog where {
+     castData = ( gTypeDialog , castToDialog )
+ } ;
+ instance CanBeCasted DragContext where {
+     castData = ( gTypeDragContext , castToDragContext )
+ } ;
+ instance CanBeCasted DrawWindow where {
+     castData = ( gTypeDrawWindow , castToDrawWindow )
+ } ;
+ instance CanBeCasted Drawable where {
+     castData = ( gTypeDrawable , castToDrawable )
+ } ;
+ instance CanBeCasted DrawingArea where {
+     castData = ( gTypeDrawingArea , castToDrawingArea )
+ } ;
+-- instance CanBeCasted Drive where {
+--     castData = ( gTypeDrive , castToDrive )
+-- } ;
+ instance CanBeCasted Editable where {
+     castData = ( gTypeEditable , castToEditable )
+ } ;
+-- instance CanBeCasted Element where {
+--     castData = ( gTypeElement , castToElement )
+-- } ;
+-- instance CanBeCasted ElementFactory where {
+--     castData = ( gTypeElementFactory , castToElementFactory )
+-- } ;
+ instance CanBeCasted Entry where {
+     castData = ( gTypeEntry , castToEntry )
+ } ;
+ instance CanBeCasted EntryCompletion where {
+     castData = ( gTypeEntryCompletion , castToEntryCompletion )
+ } ;
+ instance CanBeCasted EventBox where {
+     castData = ( gTypeEventBox , castToEventBox )
+ } ;
+ instance CanBeCasted Expander where {
+     castData = ( gTypeExpander , castToExpander )
+ } ;
+ instance CanBeCasted FileChooser where {
+     castData = ( gTypeFileChooser , castToFileChooser )
+ } ;
+ instance CanBeCasted FileChooserButton where {
+     castData = ( gTypeFileChooserButton , castToFileChooserButton )
+ } ;
+ instance CanBeCasted FileChooserDialog where {
+     castData = ( gTypeFileChooserDialog , castToFileChooserDialog )
+ } ;
+ instance CanBeCasted FileChooserWidget where {
+     castData = ( gTypeFileChooserWidget , castToFileChooserWidget )
+ } ;
+ instance CanBeCasted FileFilter where {
+     castData = ( gTypeFileFilter , castToFileFilter )
+ } ;
+ instance CanBeCasted FileSelection where {
+     castData = ( gTypeFileSelection , castToFileSelection )
+ } ;
+ instance CanBeCasted Fixed where {
+     castData = ( gTypeFixed , castToFixed )
+ } ;
+ instance CanBeCasted FontButton where {
+     castData = ( gTypeFontButton , castToFontButton )
+ } ;
+ instance CanBeCasted FontSelection where {
+     castData = ( gTypeFontSelection , castToFontSelection )
+ } ;
+ instance CanBeCasted FontSelectionDialog where {
+     castData = ( gTypeFontSelectionDialog , castToFontSelectionDialog )
+ } ;
+ instance CanBeCasted Frame where {
+     castData = ( gTypeFrame , castToFrame )
+ } ;
+ instance CanBeCasted GC where {
+     castData = ( gTypeGC , castToGC )
+ } ;
+-- instance CanBeCasted GLConfig where {
+--     castData = ( gTypeGLConfig , castToGLConfig )
+-- } ;
+-- instance CanBeCasted GLContext where {
+--     castData = ( gTypeGLContext , castToGLContext )
+-- } ;
+-- instance CanBeCasted GLDrawable where {
+--     castData = ( gTypeGLDrawable , castToGLDrawable )
+-- } ;
+-- instance CanBeCasted GLPixmap where {
+--     castData = ( gTypeGLPixmap , castToGLPixmap )
+-- } ;
+-- instance CanBeCasted GLWindow where {
+--     castData = ( gTypeGLWindow , castToGLWindow )
+-- } ;
+-- instance CanBeCasted GhostPad where {
+--     castData = ( gTypeGhostPad , castToGhostPad )
+-- } ;
+ instance CanBeCasted HBox where {
+     castData = ( gTypeHBox , castToHBox )
+ } ;
+ instance CanBeCasted HButtonBox where {
+     castData = ( gTypeHButtonBox , castToHButtonBox )
+ } ;
+ instance CanBeCasted HPaned where {
+     castData = ( gTypeHPaned , castToHPaned )
+ } ;
+ instance CanBeCasted HScale where {
+     castData = ( gTypeHScale , castToHScale )
+ } ;
+ instance CanBeCasted HScrollbar where {
+     castData = ( gTypeHScrollbar , castToHScrollbar )
+ } ;
+ instance CanBeCasted HSeparator where {
+     castData = ( gTypeHSeparator , castToHSeparator )
+ } ;
+ instance CanBeCasted HandleBox where {
+     castData = ( gTypeHandleBox , castToHandleBox )
+ } ;
+ instance CanBeCasted IconFactory where {
+     castData = ( gTypeIconFactory , castToIconFactory )
+ } ;
+ instance CanBeCasted IconView where {
+     castData = ( gTypeIconView , castToIconView )
+ } ;
+ instance CanBeCasted Image where {
+     castData = ( gTypeImage , castToImage )
+ } ;
+ instance CanBeCasted ImageMenuItem where {
+     castData = ( gTypeImageMenuItem , castToImageMenuItem )
+ } ;
+-- instance CanBeCasted ImplementsInterface where {
+--     castData = ( gTypeImplementsInterface , castToImplementsInterface )
+-- } ;
+-- instance CanBeCasted Index where {
+--     castData = ( gTypeIndex , castToIndex )
+-- } ;
+-- instance CanBeCasted IndexFactory where {
+--     castData = ( gTypeIndexFactory , castToIndexFactory )
+-- } ;
+ instance CanBeCasted Label where {
+     castData = ( gTypeLabel , castToLabel )
+ } ;
+ instance CanBeCasted Layout where {
+     castData = ( gTypeLayout , castToLayout )
+ } ;
+ instance CanBeCasted Menu where {
+     castData = ( gTypeMenu , castToMenu )
+ } ;
+ instance CanBeCasted MenuBar where {
+     castData = ( gTypeMenuBar , castToMenuBar )
+ } ;
+ instance CanBeCasted MenuItem where {
+     castData = ( gTypeMenuItem , castToMenuItem )
+ } ;
+ instance CanBeCasted MenuShell where {
+     castData = ( gTypeMenuShell , castToMenuShell )
+ } ;
+ instance CanBeCasted MenuToolButton where {
+     castData = ( gTypeMenuToolButton , castToMenuToolButton )
+ } ;
+-- instance CanBeCasted Message where {
+--     castData = ( gTypeMessage , castToMessage )
+-- } ;
+ instance CanBeCasted MessageDialog where {
+     castData = ( gTypeMessageDialog , castToMessageDialog )
+ } ;
+-- instance CanBeCasted MiniObject where {
+--     castData = ( gTypeMiniObject , castToMiniObject )
+-- } ;
+ instance CanBeCasted Misc where {
+     castData = ( gTypeMisc , castToMisc )
+ } ;
+ instance CanBeCasted Notebook where {
+     castData = ( gTypeNotebook , castToNotebook )
+ } ;
+ instance CanBeCasted Object where {
+     castData = ( gTypeObject , castToObject )
+ } ;
+ instance CanBeCasted OptionMenu where {
+     castData = ( gTypeOptionMenu , castToOptionMenu )
+ } ;
+-- instance CanBeCasted Pad where {
+--     castData = ( gTypePad , castToPad )
+-- } ;
+-- instance CanBeCasted PadTemplate where {
+--     castData = ( gTypePadTemplate , castToPadTemplate )
+-- } ;
+ instance CanBeCasted Paned where {
+     castData = ( gTypePaned , castToPaned )
+ } ;
+-- instance CanBeCasted Pipeline where {
+--     castData = ( gTypePipeline , castToPipeline )
+-- } ;
+ instance CanBeCasted Pixbuf where {
+     castData = ( gTypePixbuf , castToPixbuf )
+ } ;
+ instance CanBeCasted Plug where {
+     castData = ( gTypePlug , castToPlug )
+ } ;
+-- instance CanBeCasted Plugin where {
+--     castData = ( gTypePlugin , castToPlugin )
+-- } ;
+-- instance CanBeCasted PluginFeature where {
+--     castData = ( gTypePluginFeature , castToPluginFeature )
+-- } ;
+ instance CanBeCasted ProgressBar where {
+     castData = ( gTypeProgressBar , castToProgressBar )
+ } ;
+-- instance CanBeCasted PushSrc where {
+--     castData = ( gTypePushSrc , castToPushSrc )
+-- } ;
+-- instance CanBeCasted Query where {
+--     castData = ( gTypeQuery , castToQuery )
+-- } ;
+ instance CanBeCasted RadioAction where {
+     castData = ( gTypeRadioAction , castToRadioAction )
+ } ;
+ instance CanBeCasted RadioButton where {
+     castData = ( gTypeRadioButton , castToRadioButton )
+ } ;
+ instance CanBeCasted RadioMenuItem where {
+     castData = ( gTypeRadioMenuItem , castToRadioMenuItem )
+ } ;
+ instance CanBeCasted RadioToolButton where {
+     castData = ( gTypeRadioToolButton , castToRadioToolButton )
+ } ;
+ instance CanBeCasted Range where {
+     castData = ( gTypeRange , castToRange )
+ } ;
+-- instance CanBeCasted Registry where {
+--     castData = ( gTypeRegistry , castToRegistry )
+-- } ;
+ instance CanBeCasted Scale where {
+     castData = ( gTypeScale , castToScale )
+ } ;
+ instance CanBeCasted Screen where {
+     castData = ( gTypeScreen , castToScreen )
+ } ;
+ instance CanBeCasted Scrollbar where {
+     castData = ( gTypeScrollbar , castToScrollbar )
+ } ;
+ instance CanBeCasted ScrolledWindow where {
+     castData = ( gTypeScrolledWindow , castToScrolledWindow )
+ } ;
+ instance CanBeCasted Separator where {
+     castData = ( gTypeSeparator , castToSeparator )
+ } ;
+ instance CanBeCasted SeparatorMenuItem where {
+     castData = ( gTypeSeparatorMenuItem , castToSeparatorMenuItem )
+ } ;
+ instance CanBeCasted SeparatorToolItem where {
+     castData = ( gTypeSeparatorToolItem , castToSeparatorToolItem )
+ } ;
+ instance CanBeCasted SizeGroup where {
+     castData = ( gTypeSizeGroup , castToSizeGroup )
+ } ;
+ instance CanBeCasted Socket where {
+     castData = ( gTypeSocket , castToSocket )
+ } ;
+-- instance CanBeCasted SourceBuffer where {
+--     castData = ( gTypeSourceBuffer , castToSourceBuffer )
+-- } ;
+-- instance CanBeCasted SourceLanguage where {
+--     castData = ( gTypeSourceLanguage , castToSourceLanguage )
+-- } ;
+-- instance CanBeCasted SourceLanguageManager where {
+--     castData = ( gTypeSourceLanguageManager , castToSourceLanguageManager )
+-- } ;
+-- instance CanBeCasted SourceMark where {
+--     castData = ( gTypeSourceMark , castToSourceMark )
+-- } ;
+-- instance CanBeCasted SourceStyleScheme where {
+--     castData = ( gTypeSourceStyleScheme , castToSourceStyleScheme )
+-- } ;
+-- instance CanBeCasted SourceView where {
+--     castData = ( gTypeSourceView , castToSourceView )
+-- } ;
+ instance CanBeCasted SpinButton where {
+     castData = ( gTypeSpinButton , castToSpinButton )
+ } ;
+ instance CanBeCasted StatusIcon where {
+     castData = ( gTypeStatusIcon , castToStatusIcon )
+ } ;
+ instance CanBeCasted Statusbar where {
+     castData = ( gTypeStatusbar , castToStatusbar )
+ } ;
+ instance CanBeCasted Style where {
+     castData = ( gTypeStyle , castToStyle )
+ } ;
+-- instance CanBeCasted SystemClock where {
+--     castData = ( gTypeSystemClock , castToSystemClock )
+-- } ;
+ instance CanBeCasted Table where {
+     castData = ( gTypeTable , castToTable )
+ } ;
+ instance CanBeCasted TearoffMenuItem where {
+     castData = ( gTypeTearoffMenuItem , castToTearoffMenuItem )
+ } ;
+ instance CanBeCasted TextBuffer where {
+     castData = ( gTypeTextBuffer , castToTextBuffer )
+ } ;
+ instance CanBeCasted TextMark where {
+     castData = ( gTypeTextMark , castToTextMark )
+ } ;
+ instance CanBeCasted TextTag where {
+     castData = ( gTypeTextTag , castToTextTag )
+ } ;
+ instance CanBeCasted TextTagTable where {
+     castData = ( gTypeTextTagTable , castToTextTagTable )
+ } ;
+ instance CanBeCasted TextView where {
+     castData = ( gTypeTextView , castToTextView )
+ } ;
+ instance CanBeCasted ToggleAction where {
+     castData = ( gTypeToggleAction , castToToggleAction )
+ } ;
+ instance CanBeCasted ToggleButton where {
+     castData = ( gTypeToggleButton , castToToggleButton )
+ } ;
+ instance CanBeCasted ToggleToolButton where {
+     castData = ( gTypeToggleToolButton , castToToggleToolButton )
+ } ;
+ instance CanBeCasted ToolButton where {
+     castData = ( gTypeToolButton , castToToolButton )
+ } ;
+ instance CanBeCasted ToolItem where {
+     castData = ( gTypeToolItem , castToToolItem )
+ } ;
+ instance CanBeCasted Toolbar where {
+     castData = ( gTypeToolbar , castToToolbar )
+ } ;
+ instance CanBeCasted Tooltips where {
+     castData = ( gTypeTooltips , castToTooltips )
+ } ;
+ instance CanBeCasted TreeModel where {
+     castData = ( gTypeTreeModel , castToTreeModel )
+ } ;
+ instance CanBeCasted TreeModelSort where {
+     castData = ( gTypeTreeModelSort , castToTreeModelSort )
+ } ;
+ instance CanBeCasted TreeSelection where {
+     castData = ( gTypeTreeSelection , castToTreeSelection )
+ } ;
+ instance CanBeCasted TreeSortable where {
+     castData = ( gTypeTreeSortable , castToTreeSortable )
+ } ;
+ instance CanBeCasted TreeView where {
+     castData = ( gTypeTreeView , castToTreeView )
+ } ;
+ instance CanBeCasted TreeViewColumn where {
+     castData = ( gTypeTreeViewColumn , castToTreeViewColumn )
+ } ;
+ instance CanBeCasted UIManager where {
+     castData = ( gTypeUIManager , castToUIManager )
+ } ;
+ instance CanBeCasted VBox where {
+     castData = ( gTypeVBox , castToVBox )
+ } ;
+ instance CanBeCasted VButtonBox where {
+     castData = ( gTypeVButtonBox , castToVButtonBox )
+ } ;
+ instance CanBeCasted VPaned where {
+     castData = ( gTypeVPaned , castToVPaned )
+ } ;
+ instance CanBeCasted VScale where {
+     castData = ( gTypeVScale , castToVScale )
+ } ;
+ instance CanBeCasted VScrollbar where {
+     castData = ( gTypeVScrollbar , castToVScrollbar )
+ } ;
+ instance CanBeCasted VSeparator where {
+     castData = ( gTypeVSeparator , castToVSeparator )
+ } ;
+ instance CanBeCasted Viewport where {
+     castData = ( gTypeViewport , castToViewport )
+ } ;
+-- instance CanBeCasted Volume where {
+--     castData = ( gTypeVolume , castToVolume )
+-- } ;
+ instance CanBeCasted Widget where {
+     castData = ( gTypeWidget , castToWidget )
+ } ;
+ instance CanBeCasted Window where {
+     castData = ( gTypeWindow , castToWindow )
+ } ;
+ instance CanBeCasted WindowGroup where {
+     castData = ( gTypeWindowGroup , castToWindowGroup )
+ }
+
+}
diff --git a/src/Graphics/UI/Gtk/Layout/Rpn.hs b/src/Graphics/UI/Gtk/Layout/Rpn.hs
new file mode 100644
--- /dev/null
+++ b/src/Graphics/UI/Gtk/Layout/Rpn.hs
@@ -0,0 +1,374 @@
+module Graphics.UI.Gtk.Layout.Rpn where { import Graphics.UI.Gtk hiding
+( get ) ; import qualified Data.Word ; import Data.Monoid ; import
+Control.Monad.State ;
+import Graphics.UI.Gtk.Types ;
+import Graphics.Rendering.Cairo ;
+import Graphics.UI.Gtk.Gdk.EventM ;
+import Data.IORef ;
+import Data.Maybe ;
+import Data.List ;
+import CanBeCasted ;
+
+ doNothing :: (Monad m) => m () ;
+ doNothing = return () ;
+
+ maybeDoNothing :: (Monad m) => Maybe a -> ( a -> m b ) -> m () ;
+ maybeDoNothing a f = maybe doNothing f' a
+     where { f' a = f a >> doNothing } ;
+
+ type ActionType a = StateT [ Widget ] IO a ;
+
+ pushWidget :: ( WidgetClass w ) => w -> ActionType () ;
+ pushWidget w = modify ( toWidget w : ) ;
+
+ touchWidget :: ( CanBeCasted a ) => ( a -> IO b ) -> ActionType () ;
+ touchWidget f = do {
+     w <- ( liftM $ take 1 ) get ;
+     case mapMaybe glibCast w of {
+         [ w' ] -> liftIO $ f w' >> doNothing ;
+         _ -> doNothing
+     }
+ } ;
+
+ reachWidget :: ( CanBeCasted a ) => Int -> ActionType ( Maybe a ) ;
+ reachWidget n = do {
+     s <- get ;
+     return $ if length s > n
+         then glibCast ( s !! n )
+         else Nothing
+ } ;
+
+ pullWidget :: ( CanBeCasted a , CanBeCasted b ) =>
+ ( a -> b -> IO c ) -> ActionType () ;
+ pullWidget f = do {
+     w0 <- reachWidget 0 ;
+     w1 <- reachWidget 1 ;
+     case ( w0 , w1 ) of {
+         ( Just w0' , Just w1' ) -> do {
+             liftIO $ f w0' w1' ;
+             ( s : ss ) <- get ;
+             put $ s : drop 1 ss
+         } ;
+         _ -> doNothing
+     }
+ } ;
+
+ pullWidget3 :: ( CanBeCasted a , CanBeCasted b , CanBeCasted c ,
+ CanBeCasted d ) => ( a -> b -> c -> d -> IO e ) -> ActionType () ;
+ pullWidget3 f = do {
+     w0 <- reachWidget 0 ;
+     w1 <- reachWidget 1 ;
+     w2 <- reachWidget 2 ;
+     w3 <- reachWidget 3 ;
+     case ( w0 , w1 , w2 , w3 ) of {
+         ( Just w0 , Just w1 , Just w2 , Just w3 ) -> do {
+             liftIO $ f w0 w1 w2 w3 ;
+             ( s : ss ) <- get ;
+             put $ s : drop 3 ss
+         } ;
+         _ -> doNothing
+     }
+ } ;
+
+ newtype RPN = RPN ( ActionType () ) ;
+
+ instance Monoid RPN where { mempty = RPN doNothing ; mappend ( RPN
+ rpn1 ) ( RPN rpn2 ) = RPN $ rpn1 >> rpn2 } ;
+
+ widgetsFromRpn :: RPN -> IO [ Widget ] ;
+ widgetsFromRpn ( RPN rpn ) = ( liftM $ reverse )  ( execStateT rpn [] ) ;
+
+ io2rpn :: ( WidgetClass w ) => IO w -> RPN ;
+ io2rpn = RPN . ( >>= pushWidget ) . liftIO ;
+
+ cWID = RPN . pushWidget ;
+ cACL = io2rpn . accelLabelNew ;
+ cALN = ((( io2rpn .).).). alignmentNew ;
+ cARW = ( io2rpn .). arrowNew ;
+ cAFR = (( io2rpn .).). aspectFrameNew ;
+ cBTN = io2rpn buttonNew ;
+ cBTNSTK = io2rpn . buttonNewFromStock ;
+ cBTNL = io2rpn . buttonNewWithLabel ;
+ cBTNMNM = io2rpn . buttonNewWithMnemonic ;
+ cCLD = io2rpn calendarNew ;
+ cCVW = io2rpn cellViewNew ;
+ cCVWPIX = io2rpn . cellViewNewWithPixbuf ;
+ cCVWMRK = io2rpn . cellViewNewWithMarkup ;
+ cCVWTXT = io2rpn . cellViewNewWithText ;
+ cBTNCHK = io2rpn checkButtonNew ;
+ cBTNCHKL = io2rpn . checkButtonNewWithLabel ;
+ cBTNCHKMNM = io2rpn . checkButtonNewWithMnemonic ;
+ cMENCHKIT = io2rpn checkMenuItemNew ;
+ cMENCHKITL = io2rpn . checkMenuItemNewWithLabel ;
+ cMENCHKITMNM = io2rpn . checkMenuItemNewWithMnemonic ;
+ cBTNCLR = io2rpn colorButtonNew ;
+ cBTNCLRCL = io2rpn . colorButtonNewWithColor ;
+ cCLRSEL = io2rpn colorSelectionNew ;
+ cCMBENY = io2rpn comboBoxEntryNew ;
+ cCMBENYTXT = io2rpn comboBoxEntryNewText ;
+ cCMBENYMDL = io2rpn . comboBoxEntryNewWithModel ;
+ cCMB = io2rpn comboBoxNew ;
+ cCMBTXT = io2rpn comboBoxNewText ;
+ cCMBMDL = io2rpn . comboBoxNewWithModel ;
+ cDRW = io2rpn drawingAreaNew ;
+ cENY = io2rpn entryNew ;
+ cEVN = io2rpn eventBoxNew ;
+ cEXN = io2rpn . expanderNew ;
+ cEXNMNM = io2rpn . expanderNewWithMnemonic ;
+ cBTNFLE = ( io2rpn .). fileChooserButtonNew ;
+ cFLESEL = io2rpn . fileChooserWidgetNew ;
+ cFXD = io2rpn fixedNew ;
+ cBTNFON = io2rpn fontButtonNew ;
+ cBTNFONFN = io2rpn . fontButtonNewWithFont ;
+ cFONSEL = io2rpn fontSelectionNew ;
+ cFRM = io2rpn frameNew ;
+ cHBX = ( io2rpn .). hBoxNew ;
+ cHBXBTN = io2rpn hButtonBoxNew ;
+ cHPD = io2rpn hPanedNew ;
+ cHSC = io2rpn . hScaleNew ;
+ cHSCRNG = (( io2rpn .).). hScaleNewWithRange ;
+ cHSB = io2rpn . hScrollbarNew ;
+ cHSBDF = io2rpn hScrollbarNewDefaults ;
+ cHSP = io2rpn hSeparatorNew ;
+ cHNB = io2rpn handleBoxNew ;
+ cIVW = io2rpn iconViewNew ;
+ cIVWMDL = io2rpn . iconViewNewWithModel ;
+ cMENIMGIT = io2rpn imageMenuItemNew ;
+ cMENIMGITSTK = io2rpn . imageMenuItemNewFromStock ;
+ cMENIMGITL = io2rpn . imageMenuItemNewWithLabel ;
+ cMENIMGITMNM = io2rpn . imageMenuItemNewWithMnemonic ;
+ cIMG = io2rpn imageNew ;
+ cIMGFLE = io2rpn . imageNewFromFile ;
+ cIMGICN = ( io2rpn .). imageNewFromIconName ;
+ cIMGPIX = io2rpn . imageNewFromPixbuf ;
+ cIMGSTK = ( io2rpn .). imageNewFromStock ;
+ cLBL = io2rpn . labelNew ;
+ cLBLMNM = io2rpn . labelNewWithMnemonic ;
+ cLAY = ( io2rpn .). layoutNew ;
+ cMENBAR = io2rpn menuBarNew ;
+ cMENIT = io2rpn menuItemNew ;
+ cMENITL = io2rpn . menuItemNewWithLabel ;
+ cMENITMNM = io2rpn . menuItemNewWithMnemonic ;
+ cMEN = io2rpn menuNew ;
+ cMENTBN = ( io2rpn .). menuToolButtonNew ;
+ cMENTBNSTK = io2rpn . menuToolButtonNewFromStock ;
+ cNBK = io2rpn notebookNew ;
+ cPRB = io2rpn progressBarNew ;
+ cBTNRDI = io2rpn radioButtonNew ;
+ cBTNRDIWID = io2rpn . radioButtonNewFromWidget ;
+ cBTNRDIL = io2rpn . radioButtonNewWithLabel ;
+ cBTNRDILWID = ( io2rpn .). radioButtonNewWithLabelFromWidget ;
+ cBTNRDIMNM = io2rpn . radioButtonNewWithMnemonic ;
+ cBTNRDIMNMWID = ( io2rpn .). radioButtonNewWithMnemonicFromWidget ;
+ cMENRDIIT = io2rpn radioMenuItemNew ;
+ cMENRDIITWID = io2rpn . radioMenuItemNewFromWidget ;
+ cMENRDIITL = io2rpn . radioMenuItemNewWithLabel ;
+ cMENRDIITLWID = ( io2rpn .). radioMenuItemNewWithLabelFromWidget ;
+ cMENRDIMNM = io2rpn . radioMenuItemNewWithMnemonic ;
+ cMENRDIMNMWID = ( io2rpn .). radioMenuItemNewWithMnemonicFromWidget ;
+ cTBNRDI = io2rpn radioToolButtonNew ;
+ cTBNRDISTK = io2rpn . radioToolButtonNewFromStock ;
+ cTBNRDIWID = io2rpn . radioToolButtonNewFromWidget ;
+ cTBNRDISTKWID = ( io2rpn .). radioToolButtonNewWithStockFromWidget ;
+ cSRL = ( io2rpn .). scrolledWindowNew ;
+ cMENITSP = io2rpn separatorMenuItemNew ;
+ cTLBITSP = io2rpn separatorToolItemNew ;
+ cSKT = io2rpn socketNew ;
+ cBTNSPI = (( io2rpn .).). spinButtonNew ;
+ cBTNSPIRNG = (( io2rpn .).). spinButtonNewWithRange ;
+ cSTU = io2rpn statusbarNew ;
+ cTBL = (( io2rpn .).). tableNew ;
+ cMENITTF = io2rpn tearoffMenuItemNew ;
+ cXVW = io2rpn textViewNew ;
+ cTVWBF = io2rpn . textViewNewWithBuffer ;
+ cBTNTGL = io2rpn toggleButtonNew ;
+ cBTNTGLL = io2rpn . toggleButtonNewWithLabel ;
+ cBTNTGLMNM = io2rpn . toggleButtonNewWithMnemonic ;
+ cTLBITTLG = io2rpn toggleToolButtonNew ;
+ cTLBITTLGSTK = io2rpn . toggleToolButtonNewFromStock ;
+ cTLBITBTN = ( io2rpn .). toolButtonNew ;
+ cTLBITBTNSTK = io2rpn . toolButtonNewFromStock ;
+ cTLBIT = io2rpn toolItemNew ;
+ cTLB = io2rpn toolbarNew ;
+ cRVW = io2rpn treeViewNew ;
+ cRVWMDL = io2rpn . treeViewNewWithModel ;
+ cVBX = ( io2rpn .). vBoxNew ;
+ cVBXBTN = io2rpn vButtonBoxNew ;
+ cVPD = io2rpn vPanedNew ;
+ cVSC = io2rpn . vScaleNew ;
+ cVSCRNG = (( io2rpn .).). vScaleNewWithRange ;
+ cVSB = io2rpn . vScrollbarNew ;
+ cVSBDF = io2rpn vScrollbarNewDefaults ;
+ cVSP = io2rpn vSeparatorNew ;
+ cVWP = ( io2rpn .). viewportNew ;
+ cWND = io2rpn windowNew ;
+ cWNDPU = io2rpn windowNewPopup ;
+
+ tSET :: ( CanBeCasted w ) => [ AttrOp w ] -> RPN ;
+ tSET a = RPN $ touchWidget $ ( $ a ) . set ;
+
+ tON :: ( CanBeCasted w ) => Signal w c -> c -> RPN ;
+ tON s c = RPN $ touchWidget $ ($ c) . ($ s) . on ;
+
+ tAF :: ( CanBeCasted w ) => Signal w c -> c -> RPN ;
+ tAF s c = RPN $ touchWidget $ ($ c) . ($ s) . after ;
+
+ tSKT :: NativeWindowId -> RPN ;
+ tSKT n = RPN $ touchWidget $ ($ n) . sai
+     where { sai :: Socket -> NativeWindowId -> IO () ;
+     sai = socketAddId } ;
+
+ pCA = RPN $
+     let { ca :: Container -> Widget -> IO () ; ca = containerAdd }
+         in pullWidget ca ;
+
+ pBSI = RPN $
+     let { bsi :: Button -> Widget -> IO () ; bsi = buttonSetImage }
+         in pullWidget bsi ;
+
+ pBPS p i = RPN $
+     let { bps :: Box -> Widget -> IO () ; bps b w = boxPackStart b w p i }
+         in pullWidget bps ;
+
+ pBPE p i = RPN $
+     let { bpe :: Box -> Widget -> IO () ; bpe b w = boxPackEnd b w p i }
+         in pullWidget bpe ;
+
+ pBPSD = RPN $
+     let { bpsd :: Box -> Widget -> IO () ; bpsd = boxPackStartDefaults }
+         in pullWidget bpsd ;
+
+ pBPED = RPN $
+     let { bped :: Box -> Widget -> IO () ; bped = boxPackEndDefaults }
+         in pullWidget bped ;
+
+ pFP p = RPN $
+     let { fp :: Fixed -> Widget -> IO () ; fp f w = fixedPut f w p }
+         in pullWidget fp ;
+
+ pPA1 = RPN $
+     let { pa1 :: Paned -> Widget -> IO () ; pa1 = panedAdd1 }
+         in pullWidget pa1 ;
+
+ pPA2 = RPN $
+     let { pa2 :: Paned -> Widget -> IO () ; pa2 = panedAdd2 }
+         in pullWidget pa2 ;
+
+ pPP1 r s = RPN $
+     let { pp1 :: Paned -> Widget -> IO () ; pp1 p w = panedPack1 p w r s }
+         in pullWidget pp1 ;
+
+ pPP2 r s = RPN $
+     let { pp2 :: Paned -> Widget -> IO () ; pp2 p w = panedPack2 p w r s }
+         in pullWidget pp2 ;
+
+ pLP x y = RPN $
+     let { lp :: Layout -> Widget -> IO () ; lp l w = layoutPut l w x y }
+         in pullWidget lp ;
+
+ pNAP s = RPN $
+     let { nap :: Notebook -> Widget -> IO Int ;
+     nap l w = notebookAppendPage l w s }
+         in pullWidget nap ;
+
+ pNAPM = RPN $
+     let { napm :: Notebook -> Widget -> Widget -> Widget -> IO Int ;
+     napm = notebookAppendPageMenu }
+         in pullWidget3 napm ;
+
+ pNPP s = RPN $
+     let { npp :: Notebook -> Widget -> IO Int ;
+     npp l w = notebookPrependPage l w s }
+         in pullWidget npp ;
+
+ pNPPM = RPN $
+     let { nppm :: Notebook -> Widget -> Widget -> Widget -> IO Int ;
+     nppm = notebookPrependPageMenu }
+         in pullWidget3 nppm ;
+
+ pTA l r t b xo yo xp yp = RPN $
+     let { ta :: Table -> Widget -> IO () ; ta tab wid =
+     tableAttach tab wid l r t b xo yo xp yp }
+         in pullWidget ta ;
+
+ pTAD l r t b = RPN $
+     let { tad :: Table -> Widget -> IO () ;
+     tad ta wi = tableAttachDefaults ta wi l r t b }
+         in pullWidget tad ;
+
+ pTVACAA a = RPN $
+     let { tvacaa :: TextView -> Widget -> IO () ; tvacaa t w =
+     textViewAddChildAtAnchor t w a }
+         in pullWidget tvacaa ;
+
+ pTVACIW t x y = RPN $
+     let { tvaciw :: TextView -> Widget -> IO () ; tvaciw te wi =
+     textViewAddChildInWindow te wi t x y }
+         in pullWidget tvaciw ;
+
+ pTI i = RPN $
+     let { ti :: Toolbar -> ToolItem -> IO () ; ti tc tic =
+     toolbarInsert tc tic i }
+         in pullWidget ti ;
+
+ rCBK :: ( Widget -> IO () ) -> RPN ;
+ rCBK f = RPN $ touchWidget cb
+  where {
+      cb w = after w realize $ f w
+  } ;
+
+ rTME :: ( Widget -> IO () ) -> Int -> RPN ;
+ rTME f dt = rCBK i
+  where {
+      i w = do {
+           id <- timeoutAdd ( f w >> return True ) dt ;
+           on w unrealize $ timeoutRemove id
+      } >> return ()
+  } ;
+
+ rSHPE :: ( ( Double , Double ) -> Render () ) -> RPN ;
+ rSHPE c = mconcat [ cDRW , tON e s ]
+  where {
+      e :: Signal Widget ( EventM EExpose Bool ) ;
+      e = exposeEvent ;
+      s = do {
+           w <- eventWindow ;
+           liftIO $ do {
+               ( ww , wh ) <- liftIO $ drawableGetSize w ;
+               let { ch = c ( fromIntegral ww , fromIntegral wh ) } ;
+               liftIO $ renderWithDrawable w ch ;
+           } ;
+           return True
+      }
+  } ;
+
+ rANIM :: Int -> IO a -> ( a -> ( Double , Double ) -> Render () ) -> RPN ;
+ rANIM dt readData toRender = mconcat [ cDRW , tON e ef , tON m mf ]
+  where {
+      e :: Signal Widget ( EventM EExpose Bool ) ;
+      e = exposeEvent ;
+      ef = do {
+          dw <- eventWindow ;
+          liftIO $ do {
+              (sx,sy) <- drawableGetSize dw ;
+              let { (sx',sy') = (fromIntegral sx , fromIntegral sy) } ;
+              d <- readData ;
+              let { render = toRender d (sx',sy') } ;
+              renderWithDrawable dw render ;
+          } ;
+          return True
+      } ;
+      m :: Signal Widget ( EventM EAny Bool ) ;
+      m = mapEvent ;
+      mf = do {
+          dw <- eventWindow ;
+          liftIO $ do {
+              (sx,sy) <- drawableGetSize dw ;
+              let { area = Rectangle 0 0 sx sy } ;
+              let { f = drawWindowInvalidateRect dw area False } ;
+              timeoutAdd ( f >> return True ) dt
+          } ;
+          return True
+      }
+  } ;
+}
diff --git a/src/example.hs b/src/example.hs
new file mode 100644
--- /dev/null
+++ b/src/example.hs
@@ -0,0 +1,60 @@
+module Main where
+import Graphics.UI.Gtk
+import Graphics.UI.Gtk.Gdk.EventM
+import Graphics.Rendering.Cairo
+import Graphics.UI.Gtk.Layout.Rpn
+import Data.Monoid
+
+title :: String -> [AttrOp Window]
+title s = [windowTitle := s]
+pressed :: Signal Widget (EventM EButton Bool)
+pressed = buttonPressEvent
+
+main = do
+    initGUI
+
+    -- Create a new operator ('line') that takes a label
+    -- ('cLBL') and a button ('cBTNL') and pack then ('pBPED')
+    -- in a horizontal box ('cHBX').
+
+    let line s = mconcat [
+         cLBL (Just $ s ++ ":"),
+         cBTNL s,
+         cHBX True 0,
+         pBPED,
+         pBPED]
+
+    -- Create a new operator ('column') that packs many 'line'
+    -- in a vertical box ('cVBX').
+
+    let column = mconcat $ [
+         line "One Button",
+         line "Another Button",
+         line "Yet Another Button",
+         line "Last Button",
+         cVBX True 0] ++ replicate 4 pBPED
+
+    -- Take two copies of 'column' and add ('pNAP') then
+    -- to a notebook ('cNBK'). Then create a stock button
+    -- ('cBTNSTK') and attach a action to an event ('tON'). Then
+    -- join the notebook and that button in a vertical box.
+    -- Insert everything in a main window ('cWND, pCA'), and
+    -- finally make everything into widgets ('widgetsFromRpn').
+
+    [mainWindow] <- widgetsFromRpn $ mconcat $ [
+         column,
+         column,
+         cNBK,
+         pNAP "First Page",
+         pNAP "Second Page",
+         cBTNSTK stockQuit,
+         tON pressed (liftIO mainQuit >> return True),
+         cVBX False 0,
+         pBPE PackNatural 0,
+         pBPED,
+         cWND,
+         pCA,
+         tSET (title "Layout.RPN Example")]
+
+    widgetShowAll mainWindow
+    mainGUI
diff --git a/src/rpnCompilar.hs b/src/rpnCompilar.hs
new file mode 100644
--- /dev/null
+++ b/src/rpnCompilar.hs
@@ -0,0 +1,8 @@
+module Main where {
+import Graphics.UI.Gtk ;
+import Graphics.Rendering.Cairo ;
+import Graphics.UI.Gtk.Layout.Rpn ;
+
+ main = return ()
+
+}
diff --git a/src/rpnTeste.hs b/src/rpnTeste.hs
new file mode 100644
--- /dev/null
+++ b/src/rpnTeste.hs
@@ -0,0 +1,37 @@
+module Main where {
+import Data.Monoid ;
+import Graphics.UI.Gtk ; import Graphics.UI.Gtk.Layout.Rpn ;
+import Graphics.Rendering.Cairo ;
+
+ main = do {
+
+     initGUI ;
+
+     janelaPrincipal <- windowNew ; onDestroy janelaPrincipal mainQuit ;
+
+     [ w ] <- widgetsFromRpn $ mconcat [
+
+         cBTNSTK stockAbout ,
+         cBTNSTK stockQuit ,
+         cHBXBTN ,
+         pCA ,
+         pCA ,
+         cLBL $ Just "<b> Oi! </b>" ,
+         tSET $ ([labelUseMarkup := True] :: [AttrOp Label]) ,
+         cDRW ,
+         cVPD ,
+         pPA2 ,
+         pPA1 ,
+         cVBX False 0 ,
+         pBPE PackGrow 0 ,
+         pBPE PackNatural 0
+
+     ] ;
+
+     containerAdd janelaPrincipal w ;
+
+     widgetShowAll janelaPrincipal ;    mainGUI
+
+ }
+
+}
diff --git a/src/rpnTeste2.hs b/src/rpnTeste2.hs
new file mode 100644
--- /dev/null
+++ b/src/rpnTeste2.hs
@@ -0,0 +1,108 @@
+module Main where {
+import Graphics.UI.Gtk ;
+import Graphics.UI.Gtk.Layout.Rpn ;
+import Graphics.Rendering.Cairo ;
+import Data.Monoid ;
+import Data.IORef ;
+
+desenharQuadrados = do {
+    dw <- eventWindow ;
+    (w,h) <- drawableGetSize ;
+
+dQ :: IORef (Double,Double) -> Int -> RPN ;
+dQ ior n = mconcat [
+    cDRW ,
+    tON widgetExposeEvent desenharQuadrados ,
+    cFRM ,
+    tSET label ,
+    pCA
+ ] where {
+    widgetExposeEvent :: Signal Widget (EventM ECrossing Bool) ;
+    widgetExposeEvent = exposeEvent ;
+    label :: [AttrOp Frame] ;
+    label = [frameLabel := ( show n ++ " cm" )] ;
+    desenharQuadrados = do {
+        dw <- eventWindow ;
+        (w,h) <- drawableGetSize ;
+        let (w',h') = (fromIntegral w, fromIntegral h) ;
+        (eX,eY) <- readIORef ior ;
+        xs <- [0,n'*eX..w'] ;
+        ys <- [0,n'*eY..h'] ;
+        renderWithDrawable dw $ do {
+
+
+main = do {
+
+ initGUI ;
+
+     janelaPrincipal <- windowNew ;
+
+     proporções <- newIORef ( 10 , 10 ) ;
+
+     let {
+         atualizarX = \v -> modifyIORef proporções $ \( _ , y ) -> ( 200 / v , y ) ;
+         atualizarY = \v -> modifyIORef proporções $ \( x , _ ) -> ( x , 200 / v ) ;
+         desenharQuadrados n = do {
+             ( px , py ) <- readIORef proporções ;
+             return $ Just $ \( w , h ) -> do {
+                 let { dx = n * px ; dy = n * py } ;
+                 sequence $ ( flip map ) [ 0 , dx .. w ] $
+                  \v -> moveTo v 0 >> lineTo v h ;
+                 sequence $ ( flip map ) [ 0 , dy .. h ] $
+                  \v -> moveTo 0 v >> lineTo w v ;
+                 stroke
+             } ;
+         } ;
+         janelinha n = mconcat [
+             rpnCairoLiveShape ( desenharQuadrados n ) 2000 ,
+             rpnFrame $ Just $ "<b> Quadrados de " ++ show n ++ " <i> cm </i></b>"
+         ] ;
+     } ;
+
+     [conteúdo] <- widgetFromRpn $ mconcat [
+
+         rpnCairoShape $ const $ rectangle 10 10 200 200 >> stroke ,
+         rpnMinimumSize 220 220 ,
+
+         rpnSetOrientation OrientationVertical ,
+         rpnScale 2 10 20 1 ( Just PosRight ) atualizarY ,
+
+         rpnSetOrientation OrientationHorizontal ,
+         rpnBox [ PackGrow , PackNatural ] ,
+
+         rpnSetOrientation OrientationHorizontal ,
+         rpnScale 2 10 20 1 ( Just PosBottom ) atualizarX ,
+
+         rpnSetOrientation OrientationVertical ,
+         rpnBox [ PackNatural , PackNatural ] ,
+
+         rpnSetAlign ( 0.5 , 0.5 ) ,
+         rpnAlign 0 0 ,
+
+         rpnSetOrientation OrientationHorizontal ,
+         rpnStockButton stockQuit mainQuit ,
+         rpnButtonBox ButtonboxCenter [False] ,
+
+         rpnSetOrientation OrientationVertical ,
+         rpnBox [ PackGrow , PackNatural ] ,
+
+         janelinha 1 ,
+         janelinha 2 ,
+         janelinha 3 ,
+         rpnBox $ take 3 $ replicate 3 PackGrow ,
+
+         rpnSetOrientation OrientationHorizontal ,
+         rpnBox [ PackNatural , PackGrow ]
+
+     ] ;
+
+     containerAdd janelaPrincipal conteúdo ;
+
+     widgetShowAll janelaPrincipal ;
+
+     mainGUI
+
+ }
+
+
+}