added gaction2.nim example, and some small fixes

README.adoc

@@ -1,6 +1,6 @@
 = High level GTK3 (and GTK4) bindings for the Nim programming language
 (c) Stefan Salewski                                     
-//Version 0.6.0
+//Version 0.6.1
 :experimental:
 :imagesdir: http://ssalewski.de/tmp
 :source-highlighter: pygments
@@ -1100,7 +1100,142 @@ main()
 
 While in the previous example we create only a single menu instance in proc appStartup()
 for all of our application windows, here we create a new menu for all of our instances
-in proc appActivate(). That seems to work fine, so I assume it is correct. 
+in proc appActivate(). That seems to work fine, so I assume it is correct.
+
+== GMenu and GAction with GTK Builder
+
+And here is an example from https://github.com/GNOME/gtk/blob/mainline/tests/
+which uses a combination of gaction and gmenu with a GTK builder XML file for
+the menu description. 
+
+[[gaction2.nim]]
+[source, nim]
+.gaction2.nim
+----
+# nim c gaction2.nim
+# https://github.com/GNOME/gtk/blob/mainline/tests/testgaction.c
+# gcc -Wall gaction.c -o gaction `pkg-config --cflags --libs gtk4`
+import gintro/[gtk, glib, gobject, gio]
+
+const menuData = """
+<interface>
+  <menu id="menuModel">
+    <section>
+      <item>
+        <attribute name="label">Normal Menu Item</attribute>
+        <attribute name="action">win.normal-menu-item</attribute>
+      </item>
+      <submenu>
+        <attribute name="label">Submenu</attribute>
+        <item>
+          <attribute name="label">Submenu Item</attribute>
+          <attribute name="action">win.submenu-item</attribute>
+        </item>
+      </submenu>
+      <item>
+        <attribute name="label">Toggle Menu Item</attribute>
+        <attribute name="action">win.toggle-menu-item</attribute>
+      </item>
+    </section>
+    <section>
+      <item>
+        <attribute name="label">Radio 1</attribute>
+        <attribute name="action">win.radio</attribute>
+        <attribute name="target">1</attribute>
+      </item>
+      <item>
+        <attribute name="label">Radio 2</attribute>
+        <attribute name="action">win.radio</attribute>
+        <attribute name="target">2</attribute>
+      </item>
+      <item>
+        <attribute name="label">Radio 3</attribute>
+        <attribute name="action">win.radio</attribute>
+        <attribute name="target">3</attribute>
+      </item>
+    </section>
+  </menu>
+</interface>
+"""
+
+proc changeLabelButton(action: SimpleAction; v: Variant; label: Label) =
+  label.setLabel("Text set from button")
+
+proc normalMenuItem(action: SimpleAction; v: Variant; label: Label) =
+  label.setLabel("Text set from normal menu item")
+
+proc toggleMenuItem(action: SimpleAction; v: Variant; label: Label) =
+  label.setLabel("Text set from toggle menu item")
+
+proc submenuItem(action: SimpleAction; v: Variant; label: Label) =
+  label.setLabel("Text set from submenu item")
+
+proc radio(action: SimpleAction; parameter: Variant; label: Label) =
+  var l: uint64
+  let newState: Variant = newVariantString(getString(parameter, l))
+  let str: string = "From Radio menu item " & getString(newState, l)
+  label.setLabel(str)
+
+proc bye(w: Window) =
+  mainQuit()
+  echo "Bye..."
+
+proc main =
+  gtk.init()
+  let
+    window = newWindow()
+    box = newBox(Orientation.vertical, 12)
+    menubutton = newMenuButton()
+    button1 = newButton("Change Label Text")
+    label = newLabel("Initial Text")
+    actionGroup = newSimpleActionGroup()
+
+  window.connect("destroy", gtk.mainQuit)
+  #window.connect("destroy", bye)
+
+  var action = newSimpleAction("change-label-button")
+  discard action.connect("activate", changeLabelButton, label)
+  actionGroup.addAction(action)
+
+  action = newSimpleAction("normal-menu-item")
+  discard action.connect("activate", normalMenuItem, label)
+  actionGroup.addAction(action)
+
+  var v = newVariantBoolean(true)
+  action = newSimpleActionStateful("toggle-menu-item", nil, v)
+  discard action.connect("activate", toggleMenuItem, label)
+  actionGroup.addAction(action)
+
+  action = newSimpleAction("submenu-item")
+  discard action.connect("activate", subMenuItem, label)
+  actionGroup.addAction(action)
+
+  v = newVariantString("1")
+  let vt = newVariantType("s")
+  action = newSimpleActionStateful("radio", vt, v)
+  discard action.connect("activate", radio, label)
+  actionGroup.addAction(action)
+
+  insertActionGroup(window, "win", actionGroup)
+
+  label.setMarginTop(12)
+  label.setMarginBottom(12)
+  box.add(label)
+  menubutton.setHAlign(Align.center)
+  let builder: Builder = newBuilderFromString(menuData)
+  let menuModel = builder.getMenuModel("menuModel")
+  let menu = newMenuFromModel(menuModel)
+  menuButton.setPopup(menu)
+  box.add(menubutton)
+  button1.setHalign(Align.center)
+  button1.setActionName("win.change-label-button")
+  box.add(button1)
+  window.add(box)
+  window.showAll
+  gtk.main()
+
+main()
+----
 
 == GSettings