Inheritance of purity

[deadalnix]

Le 26/02/2012 00:02, Walter Bright a écrit :
> On 2/24/2012 3:22 AM, deadalnix wrote:
>> Le 17/02/2012 17:19, Andrei Alexandrescu a écrit :
>>> On 2/17/12 8:13 AM, kenji hara wrote:
>>>> I think the lack of 'override' keyword (filed as bug 3836) should
>>>> become an error, without the phase of deprecating it. Otherwise
>>>> following case will be allowed.
>>>
>>> Yes. Walter?
>>>
>>> Andrei
>>
>> I'm surprised this isn't even mentionned in
>> http://drdobbs.com/blogs/cpp/232601305
>>
>> I definitively don't think that pushing stuff like that - I'm
>> suspecting for ego
>> reasons - ignoring some flaw of the idea is a good way to proceed.
>> This even may
>> be armfull for the language on the long run.
>>
>> With no override keyword, function can just explode on your face for
>> no aparent
>> reason in the source code you are lookign at. This isn't an issue we
>> should ignore.
>>
>> This has a pretty simple solution : don't inherit thoses attributes of
>> override
>> isn't present. On the long run, don't allow override without override
>> keyword ?
>
> Not using override is currently deprecated. Eventually, it will be
> required.
>
> Doing this precipitously breaks existing code without allowing people
> plenty of time to upgrade their code. This annoys people, and results in
> them considering D "unstable" and "unusable".
>
> I know that some do not see it as a problem to regularly introduce
> breaking changes and pull the rug out from under people every month. But
> I think that is a recipe for disaster.

True. This is why I stated « in the long run ». The solution to that is, 
IMO, a standard process to deprecate and replace a feature, with a known 
period of time, and a page on the website to annonce this.

Eventually, someday, the codebase will be that big that breaking changes 
will not be an option anymore.