[boost] Re: [optional]output

Agreed. I was going to say that an empty optional should print something, but couldn't articulate the reasons. Thanks.

Printing something only for empty optional may lead to unclear output. For example what should be an output of: optional<string> v = "empty"; optional<string> v; optional<bool> v = false; optional<bool> v; optional<int> v = 0; optional<int> v; Gennadiy