feat: added MessageReceiver trait

core/src/message_receiver.c

@@ -0,0 +1,13 @@
+#include "message_receiver.h"
+#include "stddef.h"
+
+void* message_receiver_refuse(void* self, MessageID id, void* data) {
+    return NULL;
+}
+
+MessageReceiver message_receiver_no_implementation(void* data) {
+    static IMessageReceiver const tc = {
+        .handle_message = message_receiver_refuse
+    };
+    return (MessageReceiver){.data = data, .tc = &tc};
+}

core/src/message_receiver.h

@@ -0,0 +1,36 @@
+#ifndef _fencer_message_receiver_h
+#define _fencer_message_receiver_h
+
+#include "stdint.h"
+#include "typeclass_helpers.h"
+
+typedef uint32_t MessageID;
+
+typedef struct IMessageReceiver {
+    void* (*const handle_message)(void*, MessageID, void*);
+} IMessageReceiver;
+
+typedef struct MessageReceiver {
+    void* data;
+    IMessageReceiver const* tc;
+} MessageReceiver;
+
+extern void* message_receiver_refuse(void* self, MessageID id, void* data);
+
+extern MessageReceiver message_receiver_no_implementation(void* x);
+
+#define impl_no_MessageReceiver_for(T)\
+static inline MessageReceiver T##_as_MessageReceiver(T* x) {\
+    return message_receiver_no_implementation(x);\
+}
+
+#define impl_MessageReceiver_for(T, handle_message_f)\
+static inline MessageReceiver T##_as_MessageReceiver(T* x) {\
+    TC_FN_TYPECHECK(void*, handle_message_f, T*, MessageID, void*);\
+    static IMessageReceiver const tc = {\
+        .handle_message = (void*(*const)(void*,MessageID,void*)) handle_message_f,\
+    };\
+    return (MessageReceiver){.data = x, .tc = &tc};\
+}
+
+#endif // !_fencer_message_receiver_h