Re: [boost] Re: lexicographic: review request?

From: Brian McNamara (lorgon_at_[hidden])
Date: 2003-08-29 22:49:13

> The point is, that Jan proposed to add something which has a hidden 
> overhead and I'm not sure it's a good idea. Instead of nested 
> if-else-cascades, the user could also write:
> 
> bool operator<( const person& lhs, const person& rhs )
> {
>    return
>       lhs.lastname != rhs.lastname ? lhs.lastname < rhs.lastname :
>       lhs.firstname != rhs.firstname ? lhs.firstname < rhs.firstname :
>       lhs.age < rhs.age;
> }

I am (re)appearing mid-thread, so I may have missed something along the
way, but...

What's with "!="?  I think lexicographical orderings are built only on
the assumptions of operator<, yes?  For two objects x and y, if neither
   x < y
nor
   y < x
is true, then they are in the same equivalence class, but this is not
the same thing as equality or inequality.

I just want to make sure the template parameter constraints (or macro
parameter constraints, as the case may be) are the right ones.

-- 
-Brian McNamara (lorgon_at_[hidden])