[DIP] In-place struct initialization

[cym13 via Digitalmars-d]

On Sunday, 31 July 2016 at 04:55:31 UTC, deadalnix wrote:
> On Saturday, 30 July 2016 at 21:42:42 UTC, cym13 wrote:
>> The most interesting is to use structs to mimic keyword 
>> arguments for
>> functions. By encapsulating possible arguments in a struct it 
>> is possible to
>> use in-place initialization to provide a clean interface very 
>> similar to
>> keyword arguments such as seen in python or ruby.
>>
>
> That doesn't help. In fact, it makes things worse as now 
> constructor calls and function call do not have the same 
> syntax. You've just created an holly mess in the parser.
>
> If something we should strive to get constructor call more like 
> regular function call rather than less (for instance by 
> behaving the same way when it comes to IFTI).
>
> It is also unclear how overload resolution is supposed to work.
>
> If I may suggest one thing it is to not start with the intended 
> result for the DIP, but start from the intended change int he 
> language, then, and only then, examine what comes out of it.

I don't understand this comment. This isn't about construction, 
it's about initialization, the call can occur only at one precise 
time and no there is no overload concern as there is no function 
call. The proposed change is litteraly just equivalent to the 
already existing struct initialization, just made usable:

     struct S {
         int a;
         int b;
     }

     auto s = S(b:42);
     // equivalent to
     S s = { b:42 };

Having the possibility to initialize structs without tying them 
to a variable
proves useful when combined with functions that take this struct 
but those
functions aren't directly impacted by the change.