SumType extraction

[Josh Holtrop]

On Friday, 28 June 2024 at 10:52:01 UTC, drug007 wrote:
> What prevents you from doing:
> ```D
> import std.sumtype;
>
> class Foo {}
> class Bar {}
>
> alias Item = SumType!(Foo, Bar);
>
> void main()
> {
>     Item[] items = [Item(new Foo()), Item(new Bar()), Item(new 
> Foo()), Item(new Bar())];
>     foreach (item; items)
>     {
>         item.match!(
>             (Foo v) { /* do something with foo */ },
>             (_) {}
>         );
>     }
> }
> ```
> ?
> It's more effective by the way - you check the type once only.

Nothing prevents that, and indeed I still plan to use item.match! 
like that when I need to handle multiple/all types. I just wanted 
the get! functionality when I only expect or want to handle one 
type without all the additional pattern matching syntax.

But, I think my:

```d
     if (Foo foo = item.get!Foo)
     {
         /* do something with foo */
     }
```

is still only checking the type once due to the one call to 
match! in get!, right?