Merge pull request #501 from denizzzka/const_adding

Widget methods: adding const

src/dlangui/core/collections.d

@@ -244,12 +244,7 @@ struct ObjectList(T) {
     @property int count() const { return _count; }
     alias length = count;
     /** get item by index */
-    T get(int index) {
-        assert(index >= 0 && index < _count, "child index out of range");
-        return _list[index];
-    }
-    /** get const item by index */
-    const(T) get(int index)  const {
+    inout(T) get(int index) inout {
         assert(index >= 0 && index < _count, "child index out of range");
         return _list[index];
     }

src/dlangui/widgets/controls.d

@@ -95,7 +95,7 @@ class TextWidget : Widget {
 
     protected UIString _text;
     /// get widget text
-    override @property dstring text() { return _text; }
+    override @property dstring text() const { return _text; }
     /// set text to show
     override @property Widget text(dstring s) { 
         _text = s; 
@@ -529,7 +529,7 @@ class RadioButton : ImageTextButton {
 /// Text only button
 class Button : Widget {
     protected UIString _text;
-    override @property dstring text() { return _text; }
+    override @property dstring text() const { return _text; }
     override @property Widget text(dstring s) { _text = s; requestLayout(); return this; }
     override @property Widget text(UIString s) { _text = s; requestLayout(); return this; }
     @property Widget textResource(string s) { _text = s; requestLayout(); return this; }

src/dlangui/widgets/widget.d

@@ -1523,9 +1523,9 @@ public:
     // Widget hierarhy methods
 
     /// returns number of children of this widget
-    @property int childCount() { return 0; }
+    @property int childCount() const { return 0; }
     /// returns child by index
-    Widget child(int index) { return null; }
+    inout(Widget) child(int index) inout { return null; }
     /// adds child, returns added item
     Widget addChild(Widget item) { assert(false, "addChild: children not suported for this widget type"); }
     /// adds child, returns added item
@@ -1739,9 +1739,9 @@ class WidgetGroup : Widget {
     protected WidgetList _children;
 
     /// returns number of children of this widget
-    @property override int childCount() { return _children.count; }
+    @property override int childCount() const { return _children.count; }
     /// returns child by index
-    override Widget child(int index) { return _children.get(index); }
+    override inout(Widget) child(int index) inout { return _children.get(index); }
     /// adds child, returns added item
     override Widget addChild(Widget item) { return _children.add(item).parent(this); }
     /// inserts child at given index, returns inserted item