DIP 1031--Deprecate Brace-Style Struct Initializers--Community Review Round 1 Discussion

[aliak]

On Friday, 14 February 2020 at 07:54:56 UTC, Mathias Lang wrote:
>> You have auto?
>
> The real inconvenience shows up as you nest structure, which 
> was in the second part of the quote.
>
> Consider `auto f = Foo(a: SomeType(b: SomeOtherType(x: 42)));`, 
> it is not quite as readable as the struct literal alternative, 
> and there's no way to use `auto` here, even though the expected 
> type is known to the compiler and unambiguous.

I'm not sure I see where you're repeating types there. As for 
readability, I find

Foo f = { ber: { a: 42, b: 84 } };

Less readable than:

auto f = Foo( ber: Ber( a: 42, b: 84 ) );

(I've duplicated your spacing choices, but the extra type 
information is more useful to me at the call site).

>
> And I didn't even mention templates! Imagine if a struct is an 
> aggregate of other templated struct, e.g. `struct Aggregated 
> (T, TV = DefaultValue) { Foo!T f1; Bar!T f2; xvector!(T, TV) 
> f3; }`.
> Have fun turning a struct literal for this into something that 
> spells out the type.

That'd be not fun regardless of brace initializers or not.

>
> I would strongly advise against trying to decide what is a 
> "valid" use case. Just because someone approach a problem 
> differently doesn't mean their solution is invalid.

If there's a bug in the type system it should be fixed. Not 
maintained. Not thinking about is would be the unadvisable part 
IMO.