Re: [boost] Bounded types (or maybe not 'bounded' anymore? ;-)

From: Robert Kawulak (kawulak_at_[hidden])
Date: 2005-09-26 05:33:20

Hi, 

> Just so you know, it's my feeling that the 'range 
> constraint' is the
> most frequent and most of the more complicated cases you can 
> imagine don't
> come up that much in practice.  I'm not even sure it's really worth
> supporting.

It seems to be the most frequent and most important, but I think we
shouldn't close the door for the other
not-so-common-yet-occuring-from-time-to-time constraints, because it's easy
to let them work. One day you may need to have a type for odd numbers only,
for lowercase strings only or for strings containing numbers only, and the
template will be ready here :)

> The most important thing is to allow 
> customization of the error
> handling and set it up so the details of the constraint 
> violation can (eg: min
> or max) can be determined.  Again I've been skimming so I 
> don't know if your
> code does this or not.

Customisation of the error handling - yes, reporting details of constraints
violation - not implemented, but very easily supported.

> That's not good.  I guess you'd need need one of the policies 
> to specify the
> default value if it is allowed.  In the date-time 
> constrained_value there is
> no default constructor as I recall.

Right, in my implementation if you want to use default construction, the
policy must supply initialize() member for this purpose.

Best regards,
Robert