sumtypes for D

[Timon Gehr]

On 11/29/22 08:26, Walter Bright wrote:
> On 11/28/2022 6:53 PM, Adam D Ruppe wrote:
>> Curious, what did you find lacking in std.sumtype?
>>
>> Same question to Walter.
> 
> It's addressed in the draft DIP I just posted.
> 
> https://github.com/WalterBright/DIPs/blob/sumtypes/DIPs/1NNN-(wgb).md
> 
> ...

Maybe consider changing the syntax to something like:

sumtype ST{
     a;
     int* b;
}

The reason is that with comma-separated values, metaprogramming is hobbled.

I think we really want to be able to do things like:

sumtype ST(bool hasC){
     a;
     int* b;
     static if(hasC){
         float c;
     }
}

Similar for `static foreach`. The fact that this does not work for 
`enum`s is among the most annoying limitations of `enum`s.