On Wednesday, 18 April 2012 at 16:36:39 UTC, bearophile wrote:
> Ali:
>> That a thousandth time I have made that mistake and still have not learned. :( Yes, .nan may not be compared with any other value, including .nan.
>
> Today I'll present an enhancement request to remove this problem from D.
>
> Hugs,
> bearophile

I don't see how this could be enhanced.

On Wednesday, April 18, 2012 19:04:12 SomeDude wrote:
> On Wednesday, 18 April 2012 at 16:36:39 UTC, bearophile wrote:
> > Ali:
> >> That a thousandth time I have made that mistake and still have not learned. :( Yes, .nan may not be compared with any other value, including .nan.
> > 
> > Today I'll present an enhancement request to remove this problem from D.
> > 
> > Hugs,
> > bearophile
> 
> I don't see how this could be enhanced.

It's by design. An enhancement request is a waste of time. Comparisons with NaN _always_ return false regardless of what they're compared against - even NaN. It's not going to change.

- Jonathan M Davis

On 04/18/2012 10:13 AM, Jonathan M Davis wrote:
> On Wednesday, April 18, 2012 19:04:12 SomeDude wrote:
>> On Wednesday, 18 April 2012 at 16:36:39 UTC, bearophile wrote:
>>> Ali:
>>>> That a thousandth time I have made that mistake and still have
>>>> not learned. :( Yes, .nan may not be compared with any other
>>>> value, including .nan.
>>>
>>> Today I'll present an enhancement request to remove this
>>> problem from D.
>>>
>>> Hugs,
>>> bearophile
>>
>> I don't see how this could be enhanced.
>
> It's by design. An enhancement request is a waste of time. Comparisons with
> NaN _always_ return false regardless of what they're compared against - even
> NaN. It's not going to change.
>
> - Jonathan M Davis

It shouldn't be a problem to detect comparisons against literal .nan values. The compiler can warn with "comparison is always false".

Ali

On Wednesday, 18 April 2012 at 18:18:44 UTC, Ali Çehreli wrote:
> On 04/18/2012 10:13 AM, Jonathan M Davis wrote:
> >
> > It's by design. An enhancement request is a waste of time.
> Comparisons with
> > NaN _always_ return false regardless of what they're compared
> against - even
> > NaN. It's not going to change.
> >
> > - Jonathan M Davis
>
> It shouldn't be a problem to detect comparisons against literal .nan values. The compiler can warn with "comparison is always false".
>
> Ali

Now THAT makes sense.

On Wed, Apr 18, 2012 at 08:50:10PM +0200, SomeDude wrote:
> On Wednesday, 18 April 2012 at 18:18:44 UTC, Ali Çehreli wrote:
> >On 04/18/2012 10:13 AM, Jonathan M Davis wrote:
> >>
> >> It's by design. An enhancement request is a waste of time. Comparisons with NaN _always_ return false regardless of what they're compared against - even NaN. It's not going to change.
> >>
> >> - Jonathan M Davis
> >
> >It shouldn't be a problem to detect comparisons against literal .nan values. The compiler can warn with "comparison is always false".
> >
> >Ali
> 
> Now THAT makes sense.

+1.


T

-- 
"Computer Science is no more about computers than astronomy is about telescopes." -- E.W. Dijkstra

SomeDude:

>> It shouldn't be a problem to detect comparisons against literal .nan values. The compiler can warn with "comparison is always false".
>>
>> Ali
>
> Now THAT makes sense.

That's what my proposal is going to be, with small refinements :-) (And it think it's not the first time someone proposes it).

Bye,
bearophile

On Wednesday, April 18, 2012 11:18:44 Ali Çehreli wrote:
> On 04/18/2012 10:13 AM, Jonathan M Davis wrote:
> > On Wednesday, April 18, 2012 19:04:12 SomeDude wrote:
> >> On Wednesday, 18 April 2012 at 16:36:39 UTC, bearophile wrote:
> >>> Ali:
> >>>> That a thousandth time I have made that mistake and still have not learned. :( Yes, .nan may not be compared with any other value, including .nan.
> >>> 
> >>> Today I'll present an enhancement request to remove this problem from D.
> >>> 
> >>> Hugs,
> >>> bearophile
> >> 
> >> I don't see how this could be enhanced.
> > 
> > It's by design. An enhancement request is a waste of time.
> 
> Comparisons with
> 
> > NaN _always_ return false regardless of what they're compared against
> 
> - even
> 
> > NaN. It's not going to change.
> > 
> > - Jonathan M Davis
> 
> It shouldn't be a problem to detect comparisons against literal .nan values. The compiler can warn with "comparison is always false".

Yes, that would make sense. Heck, I'd be tempted to argue that using == with floating point values in general should be a warning, since that's pretty much never what you actually want, but that's probably not going to fly.

But the behavior itself isn't going to change.

- Jonathan M Davis

SomeDude:

>> Today I'll present an enhancement request to remove this problem from D.
>>
>> Hugs,
>> bearophile
>
> I don't see how this could be enhanced.

Take a look here:
http://forum.dlang.org/thread/undjpdewiqmghmhndedw@forum.dlang.org

Bye,
bearophile