Tagged unions [Was: What's wrong with std.variant.Variant?]

[Dukc]

On Monday, 15 June 2020 at 16:30:17 UTC, Paul Backus wrote:
>
> SumType does not implement any member functions other than the 
> ones listed in its documentation [1]: opAssign, opEquals, 
> toString, and toHash.
>
> I am curious how you arrived at this misconception.

By cutting corners when doing research. Sorry.

> Is there a way I can improve SumType's documentation to make 
> its behavior in this regard clearer?

It's not documentations fault. But if you want to supersede 
Taggedalgebraic really hard, you can try convincing Mike to let 
you write a project highlight in the D blog, to raise awareness 
for thickskulls like me :D.

>
> In Rust's `enum` types you cannot access the tag directly.

Again bad research from my part. But it's something I want to do. 
Why? `final switch` statements. I may want to `return` or `break` 
directly from the switch, and in that case I can't use pattern 
matching without extra thinking. Well, on D anyway. I don't know 
about Rust.