[boost] [core] Determining interest for two new classes: readonly and newtype

Hey, I have two classes I've developed that have been used in my own projects that I think could have a place in Boost. They are outlined below. readonly<T>: This is a wrapper class for a type to replace a const-type field in a movable class. It has const access to the type so can't modify except for the move constructor and move assignment operator. This solves the problem that no fields in a movable class can be const which can cloud the intentions of a field. readonly copies the accessor patterns seen in classes such as optional and the smart pointer collection. Example: struct foo { foo() : str("hello world") {} readonlystd::string str; }; foo f; auto g = std::move(f); static_assert(std::is_move_constructible<foo>{}, ""); std::cout << *g.str << std::endl; g.str->clear() // error: non-const method. ----- newtype This is shamelessly ripped off from Haskell and provides strongly-typed typedefs to C++. It actually has two template parameters, one is an incomplete type that provides a unique identifier for this typedef. I've opted to use the name of the typedef with an '_t' suffix, the second is the raw type that it contains. Like readonly the underlying type can be accessed by operator*, operator-> and get() methods. Example: using age = newtype; age a{25}; using byte = newtype; byte b{42}; // do something with bytes (*not* any old int). void bar(const byte); bar(a); // error: wrong type wanted 'byte' got 'age' bar(b); // okay bar(89); // error: wrong type wanted 'byte' got 'int' assert(*b == 42); Any thoughts on the design and/or their place in Boost would be much appreciated. Cheers, Sam