A new WG21 paper is available. A copy is linked below, and the paper will also appear in the next normal WG21 mailing. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.
Document number: N3793
by Fernando Cacciola, Andrzej Krzemieński
optional<T>proposed here is a type that may or may not store a value of type
Tin its storage space. Its interface allows to query if a value of type
Tis currently stored, and if so, to access it. The interface is based on Fernando Cacciola's Boost.Optional library, shipping since March, 2003, and widely used. It requires no changes to core language, and breaks no existing code.