Re: [boost] [constrained_value] Constrained Value review results

Subject: Re: [boost] [constrained_value] Constrained Value review results
From: vicente.botet (vicente.botet_at_[hidden])
Date: 2010-10-17 15:36:43

----- Original Message ----- 
From: "Robert Kawulak" <robert.kawulak_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Sunday, October 17, 2010 3:29 AM
Subject: Re: [boost] [constrained_value] Constrained Value review results

> In general, the idea looks interesting and also consistent with the idea of Vicente Botet to specify bounds inclusion like this:
> 
>    bounded<int, open_c<0>, close_c<100> >
> 

> This would allow to write:
> 
>    bounded<int, bound::int_c<-10>, bound::int_c<10> >
>    bounded<int, bound::of_type<int>, bound::of_type<int> >
>    bounded<rational, bound::of_type<quarter2type>, bound::of_type<half2type> >
>    bounded<int, bound::int_c<0>, bound::of_type<big_prime> >
>    bounded<int, bound::int_c<0, bound::included>, bound::of_type<int, bound::excluded> >
> 
> Being more explicit it is also unfortunately more verbose in most cases, compared to the current syntax:
> 
>    bounded_int<int, -10, 10>
>    bounded<int>
>    bounded<rational, quarter2type, half2type>
>    bounded<int, mpl::int_<0>, big_prime>
>    bounded<int, mpl::int_<0>, int, throw_exception<>, mpl::false_, mpl::true_>

I was wondering whether the library could not define some more generic logical and comparison constraints so we can do

constrained<int, and_<greater_equal<int_<-10> >, less_equal<int_<10> > > >
constrained<int, and_<greater_equal<ratio<1,4> >, less_equal<ratio<1,2> > > >
constrained<int, and_<greater_equal<int_<0> >, less_equal<big_prime > > >
constrained<int, and_<greater<int_<0> >, less_equal<int_<10> > > >

This will cover all the bounded cases with inclusion or exclusion of the bound.

Best,
Vicente