Partially initialized structs?

[Salih Dincer]

On Wednesday, 26 February 2025 at 15:11:47 UTC, bkoie wrote:
>  stuff like this is not even necessary if you dont need it now 
> dont delcare an easy workaround is use some copy dictionary.

It's not that simple. I found the following code very 
sympathetic. You can use the same method for structures that 
contain dynamic arrays and can be customized as needed...

```d
alias MSS(T) = My_Static_Struct!T;
struct My_Static_Struct(Type)
{
   Type id = 0;
   Type[8] arr;

   alias T = typeof(this);
   @disable this ();

   static init(Type id)
   {
     T that = void;
     that.id = id;

     return that;
   }
}

alias MDS(T) = My_Dynamic_Struct!T;
struct My_Dynamic_Struct(Type)
{
   Type id;
   Type[] arr;

   alias T = typeof(this);
   @disable this ();

   static init(Type id, size_t length)
   {
     alias R = Type[];

     import std.range : uninitializedArray;
     T that = void;
     that.id = id;
     that.arr = length.uninitializedArray!R;

     return that;
   }
}

import std.stdio;
void main()
{
   alias T = ubyte;
   MSS!T[] m1;
   with(MSS!T)
   {
     m1 = [
       init(41),
       init(42)
     ];
   }
   m1.writefln!"%-(%s\n%)";

   MDS!T[] m2;
   with(MDS!T)
   {
     m2 = [
       init(41, 4),
       init(42, 8)
     ];
   }
   m2.writefln!"%-(%s\n%)";
}
/* PRINTS:

My_Static_Struct!ubyte(41, [0, 0, 0, 0, 0, 0, 0, 0])
My_Static_Struct!ubyte(42, [0, 0, 0, 0, 0, 0, 0, 0])
My_Dynamic_Struct!ubyte(41, [16, 32, 216, 47])
My_Dynamic_Struct!ubyte(42, [32, 32, 216, 47, 100, 127, 0, 0])
*/
```

SDB at 79