[boost] Re: compare

From: Jan Langer (jan_at_[hidden])
Date: 2003-03-27 16:51:35

Gennaro Prota wrote:
> Well, if we are really going to discuss such quibbles, I would also
> change "zero" to "equiv" because that's the usual "term" used for
> strict weak ordering. And I would avoid constructs like
> 
>     template <typename T>
>     compare (T const &a, T const &b)
>          : v_ (compare () (a, b).v_)  // <--
>      {}
> 
> by doing, for instance,
> 
>     class compare
>     {
>         enum result { minus, equiv, plus };
>         result v_;
> 
>         template <typename T>
>         static result do_compare(const T& a, const T& b) {
> 
>             if (a < b) return minus;
>             else if (b < a) return plus;
> 
>             return equiv;
>         }
> 
>     public:
>[...]
> };

ok, i didnt think too long about the implementation quality. but i will 
change it for the next time.

> But there are more important points I think; first of all this: if all
> I can see "from the outside" is whether v_== minus [note: this is
> 'plus' in the original code] why keeping three states internally?

because i see no reason why they should be needed. and i can also 
exchange the meaning of plus and minus, if it is prefered.
jan

-- 
jan langer ... jan_at_[hidden]
"pi ist genau drei"