[boost] Re: physical quantities (was: runtime unit-modifiable ...)

From: Daniel Frey (daniel.frey_at_[hidden])
Date: 2004-01-08 05:40:59

Anatoli Tubman wrote:
> On Wednesday 07 January 2004 11:53, Daniel Frey wrote:
> 
>>Definitly. Why isn't the current operator ^ spelled ~ anyway? Then ^
>>could have the right precedence and meaning. Think of m/s^2. Damn
>>C-ompatibility ;)
> 
> Alas, this won't help because m^2 and m^3 should have different types.
> One needs an ability to overload on integral constant expressions:

Yup. I also mentioned something like that for the constant library in a 
post. My idea is:

void f( int i ) // #1
{
    // Used if f is called with a non-ICE
}

template< int I > void f( const int I ) // #2
{
    // Used if f is called with an ICE != 2
}

template<> void f<2>( const int ) // #3
{
    // Specialized if f is called with an ICE == 2
}

int main()
{
    const int i = 2;
    f(i); // calls #1
    f(42); // calls #2
    f(2); // calls #3
}

AFAICS this extension won't break any existing (legal) code. I'm taking 
this to csc++ now as it is OT for boost...

Regards, Daniel

-- 
Daniel Frey
aixigo AG - financial solutions & technology
Schloß-Rahe-Straße 15, 52072 Aachen, Germany
fon: [phone], fax: [phone]
eMail: daniel.frey_at_[hidden], web: http://www.aixigo.de