generic
      type Data_Type (<>) is private;
   package Iterator is

type Data_Type (<>) is private;

type Data_Type_Access is access all Data_Type;

type Gtk_Text_Tag_Table_Proc is access
        procedure (Tag  : access Gtk.Text_Tag.Gtk_Text_Tag_Record'Class;
                   Data : Data_Type_Access);

procedure Foreach 
(
Table
: access Gtk_Text_Tag_Table_Record;
Proc
: Gtk_Text_Tag_Table_Proc;
Data
: Data_Type_Access);