Re: [boost] [optional] operator<(optional<T>, T) -- is it wrong?

On Fri, Nov 28, 2014 at 3:12 PM, Matt Calabrese wrote:

On Fri, Nov 28, 2014 at 11:22 AM, Gottlob Frege wrote:

...

I (strongly!) agree with the only if op<(T,T> is defined. (And famously believe op>=(optional<T>,optional<T>) should be based on op>=(T,T), instead of !op<(T,T) )

Just want to say that I think this is important and was really upset when tuple, IMHO, got it wrong.

Well, for tuples of more than one member, there is no nice way of generating all the relations *without making an assumption about how the relations are related*. So I'm fine with (and have tried to argue that) tuple, pair, vector, etc are a different category from optional, expected, variant, any,... ie one is a single-value wrapper, the other is a combination of values. one requires lexicographical, which requires assumptions, the other doesn't, and could/should thus use the proper underlying relations. Still working on it. Tony