Let's not make invariants const

[Andrei Alexandrescu]

On 8/4/12 4:45 AM, Jonathan M Davis wrote:
> D needs to work well with const, but one of the goals is also to make it so
> that it's not required if you don't want to or can't use it. Forcing
> invariants to be const goes against this. But that decision was probably made
> before the recent decisions on Object and const functions (i.e. that toString,
> toHash, opCmp, and opEquals will no longer be part of Object, so you'll be
> able to make them whatever constness you want), and I expect that it'll be
> reverted as long as it's appropriately pointed out to Walter (though it may
> require someone else creating a pull request with the actual changes).

My opinion in the matter is that invariants are meant to be gatekeeper 
code that makes sure things stay sane and bug-free. Such code should 
have special exemptions, much like the debug statement does. Protecting 
invariants against their own bugs seems a bit extreme to me.

I think a stance could be taken either way. Const invariants are like 
the European police; non-const invariants are like US police.


Andrei