Re: [boost] Checked Integral Class

From: Dan McLeran (dan.mcleran_at_[hidden])
Date: 2005-09-15 11:28:26

I actually have a run-time version of this as well, but I prefer to use the 
compile-time version wherever I can for the reasons posted by Marciej 
Sobczak.

"Stephen Gross" <sgross_at_[hidden]> wrote in message 
news:dg9m12$p92$1_at_sea.gmane.org...
>> I've written a template class to hold a range of valid integral values. 
>> My intent was to mimic Ada's ability to define a type like this:
>>
>> type SmallInt is range -10 .. 10;
>>
>> One can then declare objects of this type and any subsequent assignment 
>> that violated this range constraint woud throw an exception.
>>
>> I have built a C++ template class that does the same thing:
>>
>> template<typename T, T min, T max>
>> struct CheckedIntegralValue
>>
>> To define a type that can hold the same range as the example above:
>>
>> typedef CheckedIntegralValue<int, -10, 10> SmallIntType;
>>
>> SmallIntType i   = -10;//OK
>> SmallIntType i2 = -100;//Will throw an exception at run-time for value 
>> out-of-range
>>
>> I won't include the whole thing here, but I can do so if there is enough 
>> interest. I have defined most of the operators one needs to use this type 
>> just as one would use a 'normal' integer.
>>
>> Would anyone be interested in something like this in the Boost libraries?
>
> Since the assignment check is done at runtime (as it has to be), why make 
> the range restriction at compile time? Isn't it more useful to have a 
> class that works more like this:
>
> === CODE ===
> CheckedIntegralValue x;
> x.setLowerLimit(-5);
> x.setUpperLimit(1000);
> x = 10;
> x = 9000; // Fails at runtime
> ===========
>
> Does this make sense?
>
> --Steve
>
>
>
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