4 files changed, 29 insertions, 0 deletions
diff --git a/src/Gtk.dcl b/src/Gtk.dcl
index 75c7754..a77e2b1 100644
--- a/src/Gtk.dcl
+++ b/src/Gtk.dcl
@@ -2,5 +2,6 @@ definition module Gtk
 
 import Gtk.Signal
 import Gtk.State
+import Gtk.Tune
 import Gtk.Types
 import Gtk.Widgets
diff --git a/src/Gtk.icl b/src/Gtk.icl
index d0e3c3a..88cb82b 100644
--- a/src/Gtk.icl
+++ b/src/Gtk.icl
@@ -2,5 +2,6 @@ implementation module Gtk
 
 import Gtk.Signal
 import Gtk.State
+import Gtk.Tune
 import Gtk.Types
 import Gtk.Widgets
diff --git a/src/Gtk/Tune.dcl b/src/Gtk/Tune.dcl
new file mode 100644
index 0000000..07d0507
--- /dev/null
+++ b/src/Gtk/Tune.dcl
@@ -0,0 +1,12 @@
+definition module Gtk.Tune
+
+from Gtk.State import :: StateT, :: Identity, :: State, :: GtkState, :: GtkM
+from Gtk.Types import :: GtkMargins
+from Gtk.Widgets import :: GtkWidget, class gtkWidget
+
+class tune elem option :: !(GtkM elem) !option -> GtkM elem
+
+(<<@) infixl 2
+(<<@) elem option :== tune elem option
+
+instance tune w GtkMargins | gtkWidget w
diff --git a/src/Gtk/Tune.icl b/src/Gtk/Tune.icl
new file mode 100644
index 0000000..26a05f3
--- /dev/null
+++ b/src/Gtk/Tune.icl
@@ -0,0 +1,15 @@
+implementation module Gtk.Tune
+
+import Control.Applicative
+import Control.Monad
+import Control.Monad.Identity
+import Control.Monad.State
+
+import Gtk
+
+instance tune w GtkMargins | gtkWidget w
+where
+	tune widgetf margins =
+		widgetf >>= \widget ->
+		setMargins margins widget >>|
+		pure widget