[boost] optional<optional<T>>

Subject: [boost] optional<optional<T>>
From: Andrei Alexandrescu (andrei_at_[hidden])
Date: 2009-09-02 22:43:10

Hello,

I'm defining an "optional" type for D's standard library modeled 
similarly to Boost.optional. An interesting question came up - should 
optional<optional<T>> fold itself into optional<T>, or is "double 
optional" an interesting concept of its own?

I thought I'd ask here because by now there's a significant body of 
experience with optional<T>. I perused the online documentation and the 
forum and couldn't find information about that specific detail.

Thanks,

Andrei