Add dot C++ impl

rt/include/python/basedef.hpp

@@ -21,4 +21,35 @@ public:
   }
 };
 
+struct function {};
+
+template <typename Func, typename Self>
+struct boundmethod {
+  [[no_unique_address]] Func func;
+  Self self;
+
+  boundmethod(Func func, Self self) : func(func), self(self) {}
+
+  template <typename... Args>
+  auto operator()(Args &&... args) const {
+    return func(self, std::forward<Args>(args)...);
+  }
+};
+
+
+template <typename Obj, std::derived_from<function> Attr>
+auto bind(Obj obj, Attr attr) {
+  return boundmethod(attr, obj);
+}
+
+template <typename Obj, typename Attr>
+  requires (! std::derived_from<Attr, function>)
+auto bind(Obj, Attr attr) {
+  return attr;
+}
+
+#define dot(OBJ, NAME) [](auto && obj) -> auto { return bind(obj, obj.NAME); }(OBJ)
+#define dotp(OBJ, NAME) [](auto && obj) -> auto { return bind(obj, obj->NAME); }(OBJ)
+
+
 #endif // TYPON_BASEDEF_HPP