Re: [boost] Design question SafeFloat

Subject: Re: [boost] Design question SafeFloat
From: Damian Vicino (damian_at_[hidden])
Date: 2018-07-28 02:37:06

Hi Steven,
Thats kind of what I would like to have, I was wondering of something like
that using "enum class" for type_safety would work.
I will give it a try and see how it goes.
Thanks for the comment.
Damian

2018-07-27 14:38 GMT-04:00 Steven Watanabe via Boost <boost_at_[hidden]>
:

> AMDG
>
> On 07/26/2018 09:25 PM, Damian Vicino via Boost wrote:
> > I'm working in simplifying safe_float to prepare it for future review.
> >
> > For now I'm focusing in a C++17 compatible version.
> >
> > Currently safefloat receives 2 template parameters:
> >
> > template<typename FP, typename P>
> > class safe_float ...
> >
> > Where FP is the floating point value being made "safe", float, double,
> long
> > double ...
> > and P is a Policy of what to check and how to react.
> >
> > <snip>
> > These are the options I'm considering
> >
> > 1) define typenames for each flag and assign them tuple of affected
> > operations
> >
> > class addition; <snip>
> >
> > template<typename R>
> > struct policy_x {
> > using reporter=R;
> > using overflow=tuple<addition>; <snip>
> > };
> >
> > 2) define typename by operation, passing class with constexprs of flags
> > being evaluated
> >
> > struct empty_check{
> > static constexpr bool check_overflow=false; <snip>
> > };
> >
> > <snip>
> >
> > 3) similar to 2, but using true_type, and false_type in place of
> constexpr
> > variables.
> > <snip>
> > 4) other options?
> >
>
> What about doing this the old-fashioned way:
>
> constexpr check_policy_t empty_check = 0;
> constexpr check_policy_t check_underflow = 0x1;
> constexpr check_policy_t check_overflow = 0x2;
> ...
>
> // with a bit of syntactic sugar:
> struct operation_id {
>   check_policy_t offset;
>   constexpr check_policy_t operator=(check_policy_t value) const
>   { return offset * value; }
> };
>
> constexpr operation_id
>   addition=0x1,
>   subtraction=0x100,
>   multiplication=0x10000
>   ...;
>
> // Usage:
> addition=check_overflow|subtraction=empty_check
>
> In Christ,
> Steven Watanabe
>
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