docs(interface): Add docs to interface macroses

src/model/interface.h

@@ -3,10 +3,43 @@
 
 #include <functional>
 
+/**
+ * @file interface.h
+ *
+ * Qt doesn't support QObject multiple inheritance. But for declaring signals
+ * in class, it should be inherit QObject. To avoid this issue, interface can
+ * provide some pure virtual methods, which allow to connect to some signal.
+ *
+ * This file provides macros to make signals declaring easly. With this macros
+ * signal-like method will be declared and implemented in one line each.
+ *
+ * @example
+ * class IExample {
+ * public:
+ *     // Like signal: void valueChanged(int value) const;
+ *     // Declare `connectTo_valueChanged` method.
+ *     DECLARE_SIGNAL(valueChanged, int value);
+ * };
+ *
+ * class Example : public QObject, public IExample {
+ * public:
+ *     // Declare real signal and implement `connectTo_valueChanged`
+ *     SIGNAL_IMPL(Example, valueChanged, int value);
+ * };
+ */
+
+/**
+ * @def DECLARE_SIGNAL
+ * @brief Decalre signal-like method. Should be used in interface
+ */
 #define DECLARE_SIGNAL(name, ...) \
     using Slot_##name = std::function<void (__VA_ARGS__)>; \
     virtual void connectTo_##name(Slot_##name slot) const = 0
 
+/**
+ * @def SIGNAL_IMPL
+ * @brief Declare signal and implement signal-like method.
+ */
 #define SIGNAL_IMPL(classname, name, ...) \
     using Slot_##name = std::function<void (__VA_ARGS__)>; \
     Q_SIGNAL void name(__VA_ARGS__); \