Re: [boost] [Boost-users] [review][constrained_value] Review of Constrained Value Library begins today

Subject: Re: [boost] [Boost-users] [review][constrained_value] Review of Constrained Value Library begins today
From: Mika Heiskanen (mika.heiskanen_at_[hidden])
Date: 2008-12-21 04:56:15

David Abrahams wrote:
> on Sat Dec 20 2008, Mika Heiskanen <mika.heiskanen-AT-fmi.fi> wrote:
> 
>> David Abrahams wrote:
>>
>>> Exceptions should almost never be used in response to broken invariants.
>> Pardon my ignorance, but how come? The constraints I have to validate usually
>> concern broken user input 
> 
> That's not a broken invariant.  A broken invariant means your program is
> broken.
> 
>> via the command line or a query string. How should I deal with them if
>> not with exceptions? Or to be more precise, why should I not use
>> constrained types for validating user input if it saves me a lot of
>> if-statements in the long run?
> 
> I would never argue that you shouldn't do that.

So you see why I would prefer the constrained value class being reviewed
to throw?

Also, pardon my ignorance again, but would you care to explain how an
expert would handle broken invariants in broken programs if not
via exceptions?  I was not aware there is a better solution.

Regards,

--> Mika Heiskanen