Re: [Boost-users] how to make fusion::pair less-than-comparable?

From: Joel de Guzman (joel_at_[hidden])
Date: 2008-08-21 10:35:22

Zeljko Vrba wrote:
> Related to my previous question: fusion::map is a sequence and instances of it
> could be directly compared with operator < , thus vectors of instances also 
> sorted if fusion::pair supported relational operators other than == and !=
> (which it doesn't).
> 
> So, two questions:
> 
> 1. What is the recommended way of defining operator< for particular pair
>    instances (e.g. for pair<net, int>) ?
> 
> 2. An explanation of why doesn't fusion::pair define at least operator< would
>    be welcome. 

The reason is I don't know (yet) how to do 1 :-) If there are some
suggestions, I see no reason why it can't be added to the library.
So... how do you compare a half-static-half-runtime pair? Compare
just the value part? How about pairs with different static parts
but comparable runtime parts, how do they compare? Simply disallow?
Comments, suggestions welcome.

Regards,
-- 
Joel de Guzman
http://www.boostpro.com
http://spirit.sf.net