DIP 1019--Named Arguments Lite--Community Review Round 2

[Yuxuan Shui]

On Wednesday, 5 June 2019 at 15:25:52 UTC, Exil wrote:
> [snip]
>> If a function is defined with some of its parameter names 
>> omitted, arguments to those parameters can labeled with an 
>> empty name.
>>
>> void fun(int);
>>
>> fun(:10);
>
> Why is this included, what is the use case for it? Why wouldn't 
> you just use fun(10) instead? If ordering is required why 
> require the ":" at all?

None of the names are required. This is provided so there is a 
way to label unnamed parameters if there is a need for it.

>
>> Overridden member functions can be called with a set of names 
>> matching any of the function definitions which are visible 
>> through the object used to call those functions.
>>
>> class A {
>>     int a(int x);
>> }
>> 
>> class B : A {
>>     override int a(int z);
>> }
>> 
>> auto b = new B;
>> A a = cast(A)b;
>> 
>> b.a(z: 1); // valid
>> b.a(x: 1); // valid
>> a.a(x: 1); // valid
>> a.a(z: 1); // error
>
> Which functions do these call? Does b.a(x: 1) call B.a() or 
> A.a()? You can call A.a() specifically, this needs to be 
> clarified as to which is called.

Parameter names have no effect on which function get called (as 
stressed by this DIP). I will clarify that more in the next 
revision.