Let's not make invariants const

[Alex Rønne Petersen]

On 05-08-2012 11:47, Simen Kjaeraas wrote:
> On Sun, 05 Aug 2012 11:36:56 +0200, Jakob Ovrum <jakobovrum at gmail.com>
> wrote:
>
>> On Friday, 3 August 2012 at 19:19:24 UTC, Alex Rønne Petersen wrote:
>>> Does anyone else find this behavior too strict?
>>
>> Yes. Sounds like yet another case of forcing bitwise const on
>> something that should only be logically const.
>>
>> Please stop forcing bitwise constancy on everything. Not everything
>> needs to work with immutable, it should be opt-in (which in this case
>> could mean explicitly marking the invariant as const) for any type.
>
> I was about to argue that non-const invariants could not be called when
> calling const or immutable member functions, but then it hit me that
> those shouldn't be able to influence the state checked by the invariant
> anyway.
>

Sure they can. If the invariant can influence something outside of the 
object, then it can potentially influence the object's members. For 
example, a global variable could hold a non-const reference to something 
that the object also has a reference to.

Aliasing is a bitch. ;)

-- 
Alex Rønne Petersen
alex at lycus.org
http://lycus.org