[boost] constrained_value question

From: Neal Becker (ndbecker2_at_[hidden])
Date: 2008-05-20 13:27:45

I have used constrained_value to prototype a fixed-pt class.  It seems to be
developing nicely.

One thing might be useful is to have the option to record minimum and
maximum values that are used during a given computation.

Right now, I have:
template<int int_bits, int frac_bits, typename base_type=int, typename
error_policy=cv::throw_exception<>, typename
round_policy=rnd<frac_bits,base_type> >
struct fixed_pt  : ...

{
  typedef fixed_pt<int_bits,frac_bits,base_type,error_policy,round_policy>
self;

  static const int total_bits = int_bits + frac_bits;
  static const base_type max = ~(base_type(-1) << (total_bits-1));
  static const base_type min = (base_type(-1) << (total_bits-1));
  typedef typename cv::bounded_int<base_type, min,
max,true,true,error_policy>::type val_t;

 ...
 val_t value;
}

So fixed_pt<> contains a bounded_int member.

I'm wondering how to add a facility to track extremal values.  It would seem
to be nice to add it into the 'value' member itself, but I suspect this
concept doesn't really fit with the constrained_value design.