2 files changed, 35 insertions, 0 deletions
diff --git a/src/Gtk/Widgets/Sheet/Signal.dcl b/src/Gtk/Widgets/Sheet/Signal.dcl
new file mode 100644
index 0000000..32f5383
--- /dev/null
+++ b/src/Gtk/Widgets/Sheet/Signal.dcl
@@ -0,0 +1,11 @@
+definition module Gtk.Widgets.Sheet.Signal
+
+from StdMaybe import :: Maybe
+
+from Gtk.Signal import class signalHandler, :: SignalHandlerInternal
+from Gtk.State import :: GtkM
+
+:: GtkSheetSignalHandler
+	= TraverseHandler !((Maybe (Int,Int)) (Int,Int) -> GtkM (Maybe (Int, Int)))
+
+instance signalHandler GtkSheetSignalHandler
diff --git a/src/Gtk/Widgets/Sheet/Signal.icl b/src/Gtk/Widgets/Sheet/Signal.icl
new file mode 100644
index 0000000..562f806
--- /dev/null
+++ b/src/Gtk/Widgets/Sheet/Signal.icl
@@ -0,0 +1,24 @@
+implementation module Gtk.Widgets.Sheet.Signal
+
+import StdEnv
+import StdMaybe
+
+import Control.Monad
+import System._Pointer
+
+import Gtk
+
+instance signalHandler GtkSheetSignalHandler
+where
+	signalName handler = case handler of
+		TraverseHandler _ -> "traverse"
+	signalHandler handler = case handler of
+		TraverseHandler f -> SHI_Int_Int_Pointer_Pointer_Bool \oldrow oldcol newrowp newcolp ->
+			let newrow = readInt4S newrowp 0; newcol = readInt4S newcolp 0 in
+			f (if (oldrow<0) Nothing (Just (oldrow,oldcol))) (newrow,newcol) >>= \r -> case r of
+				Nothing ->
+					pure False
+				Just (row,col) ->
+					appWorld (forceEval (writeInt4 newrowp 0 row)) >>|
+					appWorld (forceEval (writeInt4 newcolp 0 col)) >>|
+					pure True