[swift-evolution] Nil coalescing operator precedence

[Vladimir.S]

On 15.06.2016 16:43, Антон Жилин via swift-evolution wrote:
> `b + c * d / e` is not, obviously.

obviously, for math operators it seems like we don't need any clarifications

> `a ? b : c + x + y` -- I'd also say not, because, well, it's ternary
> operator, the special case that everyone should know (otherwise it looks
> like a mess with ? and : operators).

Yes, it's ternary operator.  But is it
a ? b : (c + x + y)
or
(a ? b : c) + x + y

IMO ambiguous.

> `a ?? x + y + z` -- maybe. If not for analogies with || and && and knowing
> about @autoclosure, I'd say that priority of ?? should be very high.
>

The same, is it
a ?? (x + y + z)
or
(a ?? x) + y + z

? I.e. I'm not asking, just show that the question is not if we know what 
does ?? mean, but how all the expression will be treated.

IMO it's totally false assumption that most of developers(and poor 
beginners) do remember the the correct precedence in such expressions and 
in most cases will not make a bug and so we should not require the 
parentheses. Imagine how each such expression will be crystal clear about 
the order of processing in *any* Swift source code you could find anywhere. 
IMO this will be great advantage of the language.

> Now that I think about it, if job of SE-0077 could be done with a linter,
> then... do we still need it?

I didn't read se-0077 in details, so have no opinion. Probably you can 
describe main ideas of it here in two words.

>
> - Anton
>
> 2016-06-15 16:00 GMT+03:00 Vladimir.S <svabox at gmail.com
> <mailto:svabox at gmail.com>>:
>
>     As I understand, the question is if
>
>     `a ?? x + y + z`
>     and
>     `a ? b : c + x + y`
>     (or `b + c * d / e`)
>
>     an "ambiguous case" ?
>
>
>     On 15.06.2016 15:42, Антон Жилин via swift-evolution wrote:
>
>         It's tempting to mention SE-0077 in this context. If it's accepted,
>         we will
>         be able to make omission of parentheses an error in ambiguous cases.
>
>         - Anton
>
>
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