Re: [boost] Checked Integral Class

From: michael toksvig (michaeltoksvig_at_[hidden])
Date: 2005-09-15 18:40:59

i agree that allowing a policy to decide whether it compiles or not is a 
superior solution

as long as the type of the addition reflects the expanded range:
    (a+b).min==a.min+b.min && (a+b).max==a.max+b.max

/michael toksvig

"Dan McLeran" <dan.mcleran_at_[hidden]> wrote in message 
news:dgcrlf$8ev$1_at_sea.gmane.org...
>I also disagree with this suggestion. I would rather leave it up to the 
>developer to specify the type of any variable. If someone gets it wrong, 
>then the policy class that deals with over/under flow will handle it.
>
> "Matt Doyle" <mdoyle_at_[hidden]> wrote in message 
> news:12F38DF504DEFB4FA6BBF26668FE96DA02A62C_at_python.a-m-c.com...
> I think I want to disagree with this suggestion. Citing your example a=b 
> should work just fine provided that the value of b will fit within the 
> constraints of a.
>
> I think in most situations (but not all) the limits are determined by how 
> the type will ultimately be used and not necessarily on the result of the 
> operation that's taking place. If it doesn't fit, so be it, it's an error.
>
> On another note; I liked that earlier suggestion of user definable error 
> handling, I can see where heavy handedness is not always desirable.
>
>> also, the type of a binary operator's return value should combine the
>> intervals of the operands
>>
>> e.g. given:
>>     CheckedIntegralValue<int, -10, 100> a;
>>     CheckedIntegralValue<int, -100, 20> b;
>>
>> then the type of a+b should be CheckedIntegralValue<int, -110, 120>
>>
>> and given:
>>     CheckedIntegralValue<int, -110, 120> sum;
>>
>> then sum = a+b, sum = a, and sum = b should all compile just fine
>>
>> conversely, a = sum, b = sum, and a = b should not
>>
>> this may have been implied, just wanted to make sure
>>
>> regards,
>>
>> /michael toksvig
>>
> <snip>
>
>
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