[dmd-beta] D 2.059 beta 4

[Don Clugston]

On 10 April 2012 05:05, Jason House <jason.james.house at gmail.com> wrote:
> On Apr 9, 2012, at 10:46 PM, Andrei Alexandrescu <andrei at erdani.com> wrote:
>
>> On 4/9/12 9:42 PM, Jason House wrote:
>>> From a safety perspective, passing strict literals as "const ref" is
>>> fine. There is no output to discard. I have a vague impression that
>>> the restriction was put in place to allow some kind of optimization.
>>> I bet it's discussed in TDPL somewhere...
>>
>> Rvalues masquerading as references to constant values have caused enormous harm to C++, culminating in the "fix" that was rvalue references.
>>
>> Let's not repeat that values. Rvalues are rvalues and should stay that way.
>
> I have never seen an explanation of D's  lack of rvalue references longer than this. Is there any online explanation/blog describing how this neatly avoids the need for the solution from C++? There has to be more to it than just creating a temporary variable when the compiler issues an error.

I haven't seen any longer explanation, either. We seem to be in a
situation where there's a problem, the only known 'solution' (from
C++) has been rejected, but without a replacement.

For nearly two years it has been one of the top items on my list of
outstanding compiler and language issues:
http://www.prowiki.org/wiki4d/wiki.cgi?LanguageDevel#DMDCompilerStability
It needs considerable thought, and a complete description of what's
wrong with the C++ approach seems to be a necessary and useful step.
BUT... I don't think we should be trying to solve this difficult issue
right now, while we are trying to get a release out the door.