std.sumtype?

[Paul Backus]

On Thursday, 25 March 2021 at 14:28:06 UTC, Atila Neves wrote:
> If one wants to do that sort of thing, yes, this is nicer. I'm 
> still at a loss as to why one would *want* to do such a thing.
>
> I think it's useful to remember that in languages where sum 
> types and pattern matching are features there's no way to do 
> this.

I suspect the big reason is that a lot of D programmers aren't 
super familiar with these languages, or with functional 
programming in general, so they find SumType's match function 
less comfortable and approachable than switching on an enum (even 
though it's fundamentally the same thing).

There's a great illustration of this in a forum thread from last 
year [1]. Once I showed how to convert the code to use SumType 
and match [2], the author could understand it, but they weren't 
able to come up with it on their own.

[1] 
https://forum.dlang.org/post/kjozzeynentyrarssnzz@forum.dlang.org
[2] 
https://forum.dlang.org/post/bzueywubiazbkxvqnaid@forum.dlang.org