add abstract base class for SelectionDescriptors to ease referencing

GUI/Models/SelectionDescriptor.h

@@ -23,6 +23,18 @@
 
 using std::function;
 
+//! Abstract base class for SelectionDescriptor to ease referencing.
+class AbstractSelectionDescriptor {
+public:
+    virtual ~AbstractSelectionDescriptor() = default;
+
+    //! Set currently selected option
+    virtual void setCurrentIndex(int newIndex) const = 0;
+
+    //! Get currently selected option
+    virtual int currentIndex() const = 0;
+};
+
 //! Describes a selection (various possibilities and the current one).
 //!
 //! Usually a selection is presented as a combo box.
@@ -38,7 +50,7 @@ using std::function;
 //! By using this class, the underlying data scheme is hidden from the user of the data. This e.g.
 //! eases SessionItem migration. The underlying implementation can be a GroupItem, a simple pointer
 //! member, a std::variant or any other construction to define a selection.
-template <typename T> class SelectionDescriptor {
+template <typename T> class SelectionDescriptor : public AbstractSelectionDescriptor {
 public:
     SelectionDescriptor() = default;
 
@@ -51,7 +63,7 @@ public:
     {
         label = item->displayName();
         options = item->value().value<ComboProperty>().getValues();
-        setCurrentIndex = [=](int index) {
+        currentIndexSetter = [=](int index) {
             ComboProperty comboProperty = item->value().value<ComboProperty>();
 
             if (comboProperty.currentIndex() != index) {
@@ -59,18 +71,22 @@ public:
                 item->setValue(QVariant::fromValue<ComboProperty>(comboProperty));
             }
         };
-        currentIndex = [=] { return item->value().value<ComboProperty>().currentIndex(); };
+        currentIndexGetter = [=] { return item->value().value<ComboProperty>().currentIndex(); };
 
         if constexpr (std::is_pointer<T>::value)
             currentItem = [=] { return dynamic_cast<T>(item->currentItem()); };
     }
 
-    QString label;                       //!< A label text (short, no trailing colon)
-    QString tooltip;                     //!< Tooltip text
-    QStringList options;                 //!< List of options, usually presented as combo entries
-    function<void(int)> setCurrentIndex; //!< Function to set currently selected option
-    function<int()> currentIndex;        //!< Function to get currently selected option
-    function<T()> currentItem;           //!< Function to get currently selected item
+    virtual void setCurrentIndex(int newIndex) const override { currentIndexSetter(newIndex); }
+
+    virtual int currentIndex() const override { return currentIndexGetter(); }
+
+    QString label;                          //!< A label text (short, no trailing colon)
+    QString tooltip;                        //!< Tooltip text
+    QStringList options;                    //!< List of options, usually presented as combo entries
+    function<void(int)> currentIndexSetter; //!< Function to set currently selected option
+    function<int()> currentIndexGetter;     //!< Function to get currently selected option
+    function<T()> currentItem;              //!< Function to get currently selected item
 };
 
 #endif // BORNAGAIN_GUI_MODELS_SELECTIONDESCRIPTOR_H