[gtkada] libglade and Windows

[Michael Bode]

Michael Bode <michael.bode at laserline.de> writes:

> > I have also read that using libglade with GtkAda is frowned upon,
> > because the use of libglade bypasses some of GtkAda's strong type
> > checking.
> 
> 
> Of course I will get problems @ run time if I define "SampleWidget" as a
> label in glade and try to use it as a button in my program, while the
> compiler would have told me @ compile time.

It's actually not as bad as I thought. Consider the following sample:

with Gtk.Main;
with Glade.XML; use Glade.XML;
with Gtk.Window; use Gtk.Window;
with Gtk.GEntry; use Gtk.GEntry;
with Gtk.Style; use Gtk.Style;
with Pango.Font; use Pango.Font;

procedure Window1 is
   XML : Glade_XML;
   Entry2 : Gtk_Entry;
   Style : Gtk_Style;
   Window1 : Gtk_Window;
begin
   Gtk.Main.Set_Locale;
   Gtk.Main.Init;
   Gtk_New (XML, "glade-test.glade");
   Window1 := Gtk_Window (Get_Widget (XML, "window1"));
   Entry2 := Gtk_Entry (Get_Widget (XML, "entry2"));
   Style := Copy (Get_Style (Window1));
   -- set some fancy font 
   Set_Font_Description (Style, From_String ("LcdD 38"));
   Set_Style (Entry2, Style);
   Gtk.Main.Main;
end Window1;

This program takes a glade file, creates the UI and then changes the
font of Entry2 to some large fancy font. If by mistake I change 

   Entry2 := Gtk_Entry (Get_Widget (XML, "entry2"));
to
   Entry2 := Gtk_Entry (Get_Widget (XML, "label2"));

where label2 is also defined in the glade file, this is checked at
this point at runtime:

raised CONSTRAINT_ERROR : window1.adb:18 tag check failed

So the error is caught as early as possible at runtime.