Slow performance compared to C++, ideas?

[Andrei Alexandrescu]

On 6/3/13 1:06 PM, David Nadlinger wrote:
> On Monday, 3 June 2013 at 16:25:24 UTC, Manu wrote:
>> You won't break every single method, they already went through that
>> recently when override was made a requirement. […] A much
>> smaller number than the breakage
>> which was gladly accepted recently. […] how did the override
>> change ever get accepted […]
>
> It appears as if either you have a interesting definition of "recently",
> or you are deliberately misleading people by bringing up that point over
> and over again.
>
> According to http://dlang.org/changelog.html, omitting "override"
> produced a warning since D 2.004, which was released back in September
> 2007! Granted, it was only actually turned from a deprecation warning
> into an actual deprecation in 2.061 (if my memory serves me right), but
> it's mostly a flaw in the handling of that particular deprecation that
> it stayed at the first level for so long. The actual language change was
> made – and user-visible – almost six (!) years ago, which is a lot on
> the D time scale.
>
> You are also ignoring the fact that in contrast to requiring "override",
> there is no clean deprecation path for your proposal, at least as far as
> I can see: Omitting the keyword started out as a warning, and IIRC still
> is allowed when you enable deprecated features via the compiler switch.
> How would a similar process look for virtual-by-default? As far as am
> isolated module with only a base class is concerned, this is not
> question of valid vs. invalid code, but a silent change in language
> semantics.
[snip]

There's one more issue with the comparison that must be clarified (I 
thought it was fairly obvious so I didn't make it explicit in my 
previous note): override is not comparable because it improves code 
correctness and maintainability, for which there is ample prior 
evidence. It's also a matter for which, unlike virtual/final, there is 
no reasonable recourse.

So invoking the cost of imposing explicit override vs imposing virtual 
as an argument for the latter is fallacious.


Andrei