[gnome-taquin] Code improvements.

[Arnaud B. <arnaudb src gnome org>]

commit 39ab4f966a1cf7e851fa058155854f2521a8fc90
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Sat Mar 2 15:40:51 2019 +0100

    Code improvements.

 data/taquin.css         |  2 +-
 src/game-headerbar.vala | 11 ++++-----
 src/game-view.vala      | 62 +++++++++++++++++++++++++++----------------------
 src/taquin-main.vala    |  2 +-
 4 files changed, 40 insertions(+), 37 deletions(-)
---
diff --git a/data/taquin.css b/data/taquin.css
index 4a0482b..b5f6ec7 100644
--- a/data/taquin.css
+++ b/data/taquin.css
@@ -25,7 +25,7 @@ button.unfullscreen-button {
 .extra-thin-window.thin-window button.new-game-button { margin-right:-6px; }
 
 /*\
-* * new-hame screen generics
+* * new-game screen generics
 \*/
 
                                .main-grid               { transition:padding 0.3s; padding:1.5rem; }
diff --git a/src/game-headerbar.vala b/src/game-headerbar.vala
index a16a8a5..89c3327 100644
--- a/src/game-headerbar.vala
+++ b/src/game-headerbar.vala
@@ -21,7 +21,7 @@
 using Gtk;
 
 [GtkTemplate (ui = "/org/gnome/Taquin/ui/game-headerbar.ui")]
-private class GameHeaderBar : BaseHeaderBar
+private class GameHeaderBar : BaseHeaderBar, AdaptativeWidget
 {
     [GtkChild] private MenuButton   history_button;
     [GtkChild] private Button       new_game_button;
@@ -49,7 +49,6 @@ private class GameHeaderBar : BaseHeaderBar
                             GameWindowFlags     flags,
                             NightLightMonitor   _night_light_monitor)
     {
-        /* Translators: usual menu entry of the hamburger menu */
         Object (about_action_label:     _about_action_label,
                 night_light_monitor:    _night_light_monitor,
                 has_keyboard_shortcuts: GameWindowFlags.SHORTCUTS in flags,
@@ -95,7 +94,7 @@ private class GameHeaderBar : BaseHeaderBar
     }
 
     /*\
-    * * Showing the Stack
+    * * showing the stack
     \*/
 
     private bool current_view_is_new_game_screen = false;
@@ -104,8 +103,6 @@ private class GameHeaderBar : BaseHeaderBar
     {
         current_view_is_new_game_screen = true;
 
-        set_subtitle (null);      // TODO save / restore?
-
         history_button.hide ();
 
         if (!game_finished && back_button.visible)
@@ -135,7 +132,7 @@ private class GameHeaderBar : BaseHeaderBar
     }
 
     /*\
-    * * Switching the Stack
+    * * switching the stack
     \*/
 
     internal void new_game ()
@@ -147,7 +144,7 @@ private class GameHeaderBar : BaseHeaderBar
     }
 
     /*\
-    * * Some public calls
+    * * some public calls
     \*/
 
     internal void new_game_button_grab_focus ()
diff --git a/src/game-view.vala b/src/game-view.vala
index 391bc8e..1111d18 100644
--- a/src/game-view.vala
+++ b/src/game-view.vala
@@ -1,22 +1,22 @@
-/* -*- Mode: vala; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
- *
- * Copyright (C) 2019 – Arnaud Bonatti <arnaud bonatti gmail com>
- *
- * This file is part of a GNOME game.
- *
- * This application is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This application is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this application. If not, see <http://www.gnu.org/licenses/>.
- */
+/* -*- Mode: vala; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+   This file is part of a GNOME game.
+
+   Copyright 2019 Arnaud Bonatti
+
+   This game is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This game is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this game.  If not, see <https://www.gnu.org/licenses/>.
+*/
 
 using Gtk;
 
@@ -54,15 +54,18 @@ private class GameView : BaseView, AdaptativeWidget
         if (GameWindowFlags.SHOW_START_BUTTON in flags)
         {
             /* Translators: when configuring a new game, label of the blue Start button (with a mnemonic 
that appears pressing Alt) */
-            start_game_button = new Button.with_mnemonic (_("_Start Game"));
-            ((!) start_game_button).get_style_context ().add_class ("start-game-button");
-            ((!) start_game_button).halign = Align.CENTER;
-            ((!) start_game_button).set_action_name ("ui.start-or-restart");
+            Button _start_game_button = new Button.with_mnemonic (_("_Start Game"));
+            _start_game_button.halign = Align.CENTER;
+            _start_game_button.set_action_name ("ui.start-or-restart");
+
+            StyleContext context = _start_game_button.get_style_context ();
+            context.add_class ("start-game-button");
+            context.add_class ("suggested-action");
             /* Translators: when configuring a new game, tooltip text of the blue Start button */
-            // start_game_button.set_tooltip_text (_("Start a new game as configured"));
-            ((StyleContext) ((!) start_game_button).get_style_context ()).add_class ("suggested-action");
-            ((!) start_game_button).show ();
-            new_game_box.pack_end ((!) start_game_button, false, false, 0);
+            // _start_game_button.set_tooltip_text (_("Start a new game as configured"));
+            _start_game_button.show ();
+            new_game_box.pack_end (_start_game_button, false, false, 0);
+            start_game_button = _start_game_button;
         }
 
         game_content = content;
@@ -88,7 +91,10 @@ private class GameView : BaseView, AdaptativeWidget
 
     internal bool game_content_visible_if_true ()
     {
-        return game_stack.get_visible_child () == game_content;
+        Widget? visible_child = game_stack.get_visible_child ();
+        if (visible_child == null)
+            assert_not_reached ();
+        return (!) visible_child == game_content;
     }
 
     internal void configure_transition (StackTransitionType transition_type,
diff --git a/src/taquin-main.vala b/src/taquin-main.vala
index da52153..71823dd 100644
--- a/src/taquin-main.vala
+++ b/src/taquin-main.vala
@@ -447,7 +447,7 @@ private class Taquin : Gtk.Application, BaseApplication
         copyright = "Copyright \xc2\xa9 2014-2019 – Arnaud Bonatti";  // TODO translation; autogen, to not 
change each year?
         documenters = { "Arnaud Bonatti" };
         logo_icon_name = "org.gnome.Taquin";
-        program_name = Taquin.PROGRAM_NAME;
+        program_name = PROGRAM_NAME;
 
         /* Translators: about dialog text; this string should be replaced by a text crediting yourselves and 
your translation team, or should be left empty. Do not translate literally! */
         translator_credits = _("translator-credits");