Re: Review Request: dlw_gcd.zip

From: helmut.zeisel_at_[hidden]
Date: 2001-08-29 14:37:13

--- In boost_at_y..., Douglas Gregor <gregod_at_c...> wrote:

> 
> It makes sense to make the algorithm work at its natural level of 
> abstraction. If a Euclidean ring is the algebraic structure on which
the 
> algorithm is defined, then it should work for all Euclidean rings.
> 
> Additionally, I think it does make sense to use a static assert in
this case, 
> especially because a Euclidean ring is a sufficiently rich
algebraic 
> structure that not all algebraic types conform to. 
> 
> What I'm saying is that the 
> 
> ::boost::extensible_traits<is_euclidian_ring_tag, T>::value
> 
> approach can get very unweildy. If I have a type Foo that models a
Euclidean 
> ring, I don't want to specialize extensible traits for the tags:
> euclidean_ring_tag
> ring_tag
> semiring_tag
> abelian_group_tag
> group_tag
> abelian_monoid_tag
> monoid_tag
> 

I agree to all three points.
The problem is, however, that to my current knowledge
I do not know a solution that satisfies all three points
simultanously.

In my personal preferences, I would drop the static
assertion -
if a class offers a %= operator
in the usual semantics,
there are good chances that it is already an Euclidian ring,
so we have already a compile time check for the most usual cases.

I, however, do not know the preferences of other people.

Maybe someone has a great idea how to satisfy all three points.

Helmut