2010/10/8 vicente.botet <vicente.botet@wanadoo.fr>:
I was wondering if we could not use Boost.Ratio to specify compile time bounds for boost::rational. So instead of
bounded<rational, quarter2type, half2type>::type my_rational(rational(1, 2));
we can do
static_bounded<rational, ratio<1,4>, ratio<1,2> >::type my_rational(rational(1, 2));
Not static_bounded, but rather bounded<rational, ratio<1,4>, ratio<1,2> >::type. ratio<1,4> is a type, not a compile time constant. Once again I'll try to explain – static_bounded (bounded_int, bounded_ct or whatever we call it) is not exactly for bounds fixed at compile time, but for bounds values of which can be expressed by compile time constants.
We can consider that ratio is the rational_constant of rational as integral_constant is the tpe constant for integral types. Of cousre, we will need to use a comparator that would be able to compare ratio and rational.
template <intmax_t N, intmax_t D> bool operator<(rational<intmax_t> const& lhs, ratio<N,D> rhs); template <intmax_t N, intmax_t D> bool operator<(ratio<N,D> lhs, rational<intmax_t> const& rhs);
Or even simpler – make ratio implicitly convertible to rational. Either way, the best place for this functionality is probably the rational class. Best regards, Robert