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

Mathias Gaunard wrote:

Jeff Garland wrote:

...

bounded_int::type hour; hour = 20; // OK hour = 26; // exception!

Behavior in case of assignment of an invalid value can be customized.

I think this is wrong. Providing an invalid value should be a non-recoverable programming error. Non-recoverable means it should abort the program, and programming error means it should only be enabled in debug mode. i.e. an assert is the best choice to assert the preconditions are met.

I disagree with your analysis. The '26' value could be a run-time calculation and not just a compile-time constant. In which case you are saying that the assignment of a run-time calculation should assert only when run in debug mode and otherwise should be ignored. I can not agree with that idea.

Apart from that, wouldn't it be more interestin, when multiplying a bounded_int by 2, to yield a bounded_int instead of attempting to keep the object with the same constraint? Of course, that only works with bounded_int and not constraints in general.

I disagree with this also. The entire idea of a constraint in this library is that the underlying value meets the criteria of the constraint and not that the constraint changes to accomodate a new underlying value.