• Mr T. (15/15) Dec 03 2020 Hello. Got a suggestion, not even a request: exhaustive struct
• Jacob Carlborg (4/23) Dec 04 2020 You can just use a constructor to achieve the same thing.
• Mr T. (2/3) Dec 04 2020 Constructors need writing, these things exist automatically.
• Q. Schroll (23/28) Dec 09 2020 True, but if you really need it multiple times, a mixin template

Mr T. <tee invalid.io> writes:

Hello. Got a suggestion, not even a request: exhaustive struct 
initializers.

Like this:

------------------------
struct Box {
     int x;
     int y;
}

void foo() {
     Box box = {x: 3};              // ok
     Box box = final {x: 3};        // error: y not initialized
     Box box = final {x: 3, y: 7};  // ok
}
------------------------

I'd appreciate this. What do you think?

Jacob Carlborg <doob me.com> writes:

On 2020-12-04 07:19, Mr T. wrote:
 Hello. Got a suggestion, not even a request: exhaustive struct 
 initializers.
 
 Like this:
 
 ------------------------
 struct Box {
      int x;
      int y;
 }
 
 void foo() {
      Box box = {x: 3};              // ok
      Box box = final {x: 3};        // error: y not initialized
      Box box = final {x: 3, y: 7};  // ok
 }
 ------------------------
 
 I'd appreciate this. What do you think?

You can just use a constructor to achieve the same thing.

-- 
/Jacob Carlborg

Mr T. <tee invalid.io> writes:

On Friday, 4 December 2020 at 15:25:13 UTC, Jacob Carlborg wrote:
 You can just use a constructor to achieve the same thing.

Constructors need writing, these things exist automatically.

Q. Schroll <qs.il.paperinik gmail.com> writes:

On Friday, 4 December 2020 at 16:15:33 UTC, Mr T. wrote:
 On Friday, 4 December 2020 at 15:25:13 UTC, Jacob Carlborg 
 wrote:
 You can just use a constructor to achieve the same thing.

 Constructors need writing, these things exist automatically.

True, but if you really need it multiple times, a mixin template 
can serve you well: A quick and easy one is

     mixin template FinalCtor()
     {
         this(typeof(this.tupleof) args)
         {
             this.tupleof[] = args[];
         }
     }

but error messages if you forget arguments are rather bad. You 
could (in increasing value but also increasing difficulty)
(1) Add a templated  disable'd overload that catches all others 
and generates a  disabled error message.
(2) Add  disable'd overload that are one or more arguments short.
(3) Use https://dlang.org/phobos/std_traits.html#FieldNameTuple 
and other reflection to actually insert the member names. That 
way, you can use named arguments as soon as the corresponding DIP 
is implemented and best error messages. This solution is very 
convoluted using string mixins and from a maintenance viewpoint 
is worse than (2).

I've done (2) in https://run.dlang.io/is/vAGRMV
and (3) in https://run.dlang.io/is/PMT1PT