Re: [boost] [mpl::math Rational] type member

From: Andy Little (andy_at_[hidden])
Date: 2005-10-24 04:08:30

"David Abrahams" wrote
> "Andy Little"  writes:
>
>> "David Abrahams"  wrote
>>> "Andy Little" writes:
>>
>>> I don't see what the presence of numerator and denominator has to do
>>> with normalization.
>>
>> They should be typedefs for  the input parameters?
>
> What does that have to do with normalization?

Are you referring to my use of the word 'normalisation'  to mean  making
my_rational<2,8>::type == my_rational<1,4>? Maybe the use of  the word
normalisation here is not correct. Is that the problem?

[cut]

>>> Who suggested a special case?
>>
>> Whoever said , " Is it daft to want my_rational<x,1> to be a
>> conforming MPL integral constant?" .
>
> That doesn't require any special case code.

At least in terms of the value and value_type members it does:

http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html

[cut]

>> Conversion is fine. Thats not what you said above.
>
> No, it's not what I said above.  Remember, the usual runtime logic
> doesn't necessarily apply.  my_rational<x,1> can be an integral
> constant *at compile time*.  I'm not sure it's useful, but it's not
> insane.

Its difficult to know what you mean.
Do you mean something like:

template <
    typename  Numerator,
    typename Denominator
>
where Denominator == One
struct my_rational : Numerator {/*...*/};

( forgetting for a moment the other cases )

regards
Andy Little