Discussion Thread: DIP 1044--Enum Type Inference--Community Review Round 1

[Timon Gehr]

On 19.11.22 05:14, Walter Bright wrote:
> 
> You're referring, of course, to the "contextual" part of the DIP, where 
> the lookup works only in a subset of cases. The contextual lookup can 
> result in some odd cases like:
> 
> ---- module A ----
>      private enum E { e; };
>      public void dra(E);
> ------------------
>      import A;
> 
>      dra($e);
> ------------------
> ...

This is a good point. However, it's an existing oddity in the language 
that public symbols can use private symbols in their signatures.

> Is that a good thing?

I think contextual lookup is better than trying to do a lookup within 
the scopes of all visible enumerations. Vladimir's suggestion where we 
would add symbol literals is even better.

I have somewhat mixed feelings about implicit `with`. On one hand, it's 
even more convenient than `$e` `_.e`, `:e` etc, but on the other hand 
it's even less predictable for a user where it will work, and it can 
shadow variables from outer scopes (which is also a breaking change).

> I'm not sure. This is also not addressed in the DIP.

I don't have particularly strong feelings about this feature either way, 
but it is quite popular and I have been annoyed by the need to write 
`with` statements in the past. (But maybe that's partly because the 
emacs d mode is not so great at indenting
switch(x) with(E){
     case a: ...
}.)